There are many AIs in the world. ChatGPT, Gemini, Claude. They are all smart and all the rage.
But I can say this with certainty: When it comes to the power to change your work, nothing beats Gemini Notebook (formerly NotebookLM).
I have been using all kinds of AI for the past four years. AI became my hobby, then my job, and I even published a book about it. And the AI I spend the most time with every day is Gemini Notebook.
My 100 hours of monthly overtime vanished; I go home on time every day and eat dinner with my children. It is no exaggeration to say it changed my life.
And yet, public awareness hasn't caught up. "NotebookLM? I've heard the name." "How is it different from ChatGPT?"—I have been asked these questions every day for a year.
That is why I am writing this article. What kind of AI is Gemini Notebook, why is it so amazing, and how can you use it for work?
I will explain it thoroughly, even for those who know nothing about AI, in the easiest way possible in Japan. I will explain technical terms in plain Japanese every time I use them. It will be a long article, but by the time you finish reading, you will definitely be thinking, "I'll try it today."
Chapter 1: This is Gemini Notebook
First, let's look at what this AI actually is. I'll go slowly, assuming zero prior knowledge.
In a word: "You can create your own AI"
To describe Gemini Notebook in one sentence:
An AI that reads the materials you give it and becomes an expert on that content.
Let me be more specific. In Gemini Notebook, you first create a box called a "notebook." Then, you put materials into that box. PDFs, Word files, Google Docs, web pages, recorded audio—anything goes.
Then—that box turns into a "consultation desk" that perfectly understands the contents of the materials you put in.
For example, a box containing your company's work regulations becomes a "desk that answers anything about work regulations."
- A box with meeting recordings becomes a "desk that remembers everything from that meeting."
- A box with client materials becomes an "expert on that client."
Do you notice? You aren't just "using AI"; you are "creating your own dedicated AI." An AI made from your materials, for you, and no one else in the world. If ChatGPT is "borrowed intelligence," Gemini Notebook is "intelligence you grow yourself." This is the fundamental difference from any other AI.
Look at an actual conversation
It's faster to show you the real thing than to explain it. For example, suppose you put a thick 100-page business manual into the box and ask this:
You: "By when and how should I apply for expense reimbursement?"
Gemini Notebook: "Expense reimbursement must be applied for by the 5th of the month following the month of use. There are three steps: (1) Enter into the dedicated form, (2) Attach the receipt image, and (3) Select the approver and submit. Note that prior application is required for amounts exceeding 50,000 yen [1][2]."
—Please pay attention to the numbers [1][2] at the end of the answer. These are citations saying, "This answer is written in this part of the manual." If you click them, you can jump to the relevant page of the manual in an instant.
In other words, you didn't read the 100 pages. Yet, you got an accurate answer with evidence in 10 seconds. The task of "reading" has turned into "asking." Can you imagine this feeling? What if all the unread materials sleeping on your desk could do this?
Not a "Smart AI," but an "AI that knows you"
Here is something important. The value of Gemini Notebook is not its "smartness." It is its "detailed knowledge."
ChatGPT and Gemini are incredibly smart. But they don't know your company's regulations. They don't know what was decided in your meetings, they don't know your customers, and they don't know you. So, no matter how smart they are, they only return "generalities of the world." Correct, but not entirely helpful for your specific needs.
Gemini Notebook is the opposite. It might not know about the world, but it knows what you gave it more accurately than anyone else. The answers you really want at work aren't "This is how it is in the world," but "This is how it is in our regulations" or "This is how it is for this project."
To summarize: ChatGPT is a know-it-all for the whole world. Gemini Notebook is your personal librarian.
You can ask a know-it-all for small talk, but the partner you want for work is the librarian who has read your entire archive.
Chapter 2: Features of Gemini Notebook—5 Reasons I Fell in Love
Now that you understand what it is, let's look at its features. I've narrowed down the answer to "How is it different from other AIs?" to five points. Let me talk about each one passionately. These are in the order of when I actually said, "This is amazing."
Feature 1: It doesn't lie—An AI that can say "I don't know"
If you've used AI for work, you've probably experienced the moment an AI tells a plausible lie.
It answers as if a non-existent regulation were real. It states slightly wrong numbers with total confidence. In the AI world, this is called "hallucination." It's not malicious, but it's fatal for work.
Answers that might be lies end up needing to be double-checked. "Working overtime to verify an AI's answer meant to save time"—it's a bad joke, but it actually happens.
Gemini Notebook is fundamentally different here. It is designed so that it cannot answer things not written in the materials you provided. If you ask something not in the materials, it returns this:
"That information is not included in the sources."
When I first saw this answer, I was moved. It was the first time I saw an AI that didn't pretend to know everything. It's the same with humans, right? You trust someone who says, "I don't know, let me check," more than someone who answers everything instantly. Gemini Notebook is that "sincere person" in the AI world. That's why you can trust it with your work.
Feature 2: Every answer comes with "Evidence"
The citation numbers [1][2] we saw in the Chapter 1 example. That is the second feature.
Gemini Notebook's answers always indicate which part of which document the answer is based on. Click the number, and you jump to the original text. In other words, you don't need to "believe" the AI's answer. You can "verify" it.
This difference is decisive in work situations. Imagine the moment your boss asks, "Where did this number come from?" or a client asks, "What is the basis for that?"
—If it's something you looked up with Gemini Notebook, you just open the original text and show them. You can answer, "It's written in Article 12 of the regulations," instead of "The AI said so."
The feeling that using an AI's answer as-is is scary is correct. This citation function removes that fear not through willpower, but through a system.
This is half the reason why I call Gemini Notebook the "AI with the best compatibility for work."
Feature 3: Not disposable—"The more you store, the smarter it gets"
The third is the difference in how you interact with it.
Think back to your conversations with ChatGPT. Even if you get a good answer, it's over once that conversation ends. The next day, you have to explain everything from scratch again. Every time is a "first meeting."
Gemini Notebook is different. The materials you put in the notebook stay there forever. A meeting notebook where you've stored minutes for a year becomes a living dictionary that remembers the entire history of the project.
A notebook where you've stored past social media posts becomes an advisor that knows your winning patterns inside out. It becomes smarter today than yesterday, and smarter tomorrow than today.
I call this "Searching is disposable, stocking is an asset." The difference between a way of working where you search every time and forget every time, and a way of working where things pile up as much as you store them. You won't see a difference in a week. But a year later, the gap will be irrecoverably wide.
My notebooks now know more about my work than anyone else in the company. Materials I put in a year ago help me today—it's a tool where your past self becomes an ally to your future self.
Feature 4: Materials "transform" into radio, maps, or slides
The fourth is a feature you'll want to show people. Gemini Notebook can transform the materials you put in into different forms.
Transform into Radio
—With one button, it generates audio where two AIs discuss the content of the materials like a radio program (this is the Audio Overview feature). They explain things in a conversational way, like "The point of this material is..." "Oh, that's interesting, because..." I listen to this every morning on the commuter train. Thick materials turn into a 20-minute program. A crowded train turns into learning time.
Transform into a Map
—With the mind map function, the overall picture of the material becomes a single branching diagram. Even for a 100-page document, you can look at the map first and click on the branches you care about to dive deeper. "I don't know where what is written" disappears.
Transform into Slides
—It automatically generates presentation slides with a clean design from the content of the materials. The time spent struggling with PowerPoint shapes completely vanishes.
Transform into a Quiz
—It automatically creates quizzes from the materials. For study, training, or certification prep. You can test if the knowledge you thought you read has actually stuck.
...Just by putting in one document, you can listen, look, present, and even test. The common sense that materials are "things to read" completely collapses here. The day I first heard the Audio Overview, I handed my phone to my family and said, "Listen to this for a second." You will probably be the same.
Feature 5: Free and safe—Built for professional use
The last feature is subtle but the most important for work.
First, you can start for free. If you have a Google account, you can start today. And the materials you upload are not used for AI training. Google explicitly states that your company's materials will not be incorporated into the AI and leaked to the world. Furthermore, if you use it with a corporate Google Workspace account, it can be operated under organizational management.
Remember. Many AIs have been stopped by the wall of "It's convenient, but I'm scared to put company information in it." Gemini Notebook is designed for the other side of that wall—working with company information as a premise.
That's why I say there is no AI with better compatibility for work than this. (Of course, check your own company's rules when using it for business. This is common etiquette for any tool.)
Chapter 3: How to use it at work—Showing you everything by scenario
"I get that it's amazing. So, how can I use it in my own work?"—This chapter is the answer. I will show you specifically how to use it and "what changes" for each work scenario. As you read, imagine your own Monday.
Meetings—The job of writing minutes disappears from this world
Record the meeting (a voice memo on your phone is fine; Gemini Notebook can read audio directly), put it in a notebook, and ask, "Summarize this into minutes. List decisions and TODOs with assignees and deadlines." Five minutes later, the minutes are complete.
I used to spend three hours on this task every time. Trying to remember who said what, organizing decisions, and identifying TODOs.
—Now I just press the record button. Being able to focus on the discussion without taking notes during the meeting was also a significant, albeit subtle, change.
Moreover, a meeting notebook where you keep storing minutes becomes an asset itself.
- "What was the conclusion on this matter last month?"
- "Who had that homework?"
—Ask the notebook, and you'll know in 10 seconds. Minutes change from a "writing job" to a "stored asset."
Inquiry Handling—"I have to ask that person to find out" disappears
Create a notebook with internal regulations and manuals and share it with the team. Just like that, a "desk" that answers internal questions 24 hours a day is complete.
- "How many days in advance do I need to apply for paid leave?"
- "When is the expense deadline?"
—Someone stops what they're doing to answer these questions every day, right? The notebook takes over all of that. Since the answers include citations of the regulations, the accuracy is guaranteed.
In my workplace, after creating and sharing four inquiry notebooks for General Affairs, Accounting, HR, and IT, 90% of inquiries vanished (I'm not exaggerating, this is measured).
I will never forget the day a General Affairs person, who had been drowning in overtime for inquiry handling, thanked me with tears in their eyes. An "internal chatbot" with zero development cost and 15 minutes of work. I truly want every company to implement this for this reason alone.
Reading Materials—All "unread piles" become an active force
Materials you need to read but haven't. Industry reports, thick specifications, contracts, manuals. Are they piling up on your desk and desktop?
Put them all in a notebook. And instead of reading, ask.
- "Give me the 5 main points."
- "Tell me only the parts relevant to us."
- "Identify all descriptions that could be risks."
—The pile of unread materials turns into an "active force that answers when asked" from that day on.
Personally, checking contracts and rules was a huge revelation. When I ask, "What clauses in this contract are disadvantageous to us?" it lists the relevant parts with citations.
Of course, the final judgment is by a human (or an expert for important things), but the first 90 minutes of reading becomes 10 minutes. When this difference accumulates every week, you get back months of time.
Creating Materials—"Writing from scratch" is gone
The real enemy of creating materials is not writing, but the blank page. Planning documents, reports, and proposals are heavy because you think about the structure from scratch.
With Gemini Notebook, just put the ingredients (market data, customer voices, past materials) into a notebook and ask, "Create a draft plan with these materials." The framework comes out in a few minutes, so your job changes from "writing from scratch" to "editing the draft."
Furthermore, if you use slide generation, even the look of the presentation materials is automatic. Use your time for thinking and let the AI handle the tidying up. The time allocation for creating materials returns to what it should be.
Learning—Commute time becomes a daily class
Catching up on a new field, studying for a certification, latest industry trends. Everyone thinks, "I have to study," but is too tired to start. So, stop studying at a desk and create a system for learning by ear.
In a notebook with materials on the theme you want to learn, generate an Audio Overview (radio version) and listen to it during your commute. At night, check your understanding with the quiz function. If there's something you don't understand, ask in the chat.
Textbooks, classes, teachers, and tests are all in one notebook. I call this a "personal school." There's no entrance fee or tuition.
It's also perfect for certification study. Have the notebook create quizzes from the textbook and explain only the questions you got wrong. The reference book changes from "something to read" to a "teacher who gives you problems."
Studying that relies on the willpower to sit at a desk doesn't last, but studying integrated into commute and gap time continues naturally. Changing learning from a matter of will to a matter of system—this is also a specialty of the "stocking AI."
Chapter 4: My Top Recommendation—The idea of stocking "People"
Up to now, we've talked about "stocking materials." In this chapter, we go one step further. The usage I want to recommend most right now. The idea of stocking "people."
"Stocking people?"—It sounds like strange English. But think about it. A person's way of thinking and judgment is expressed in the record of their words. What they said, what they wrote, what they decided. If you store those in a notebook, the AI can learn "that person's way of thinking" from those records.
In other words, if you can create an expert on materials, you can also create an "understander of people." I am growing three "people notebooks." Let me introduce them in order.
1st Notebook: Self-Notebook—The AI that knows you best in the world
First, yourself. A "Self-Notebook" that stores your strengths, weaknesses, values, past experiences, and goals.
It's easy to make: just talk to a recording app on your phone for 10 minutes about yourself. Jobs that made you happy, frustrating experiences, things you're good at, what you really want to become. You don't need to speak beautifully. Put the recording file in the notebook, and the first edition is complete (it reads audio as is).
If you usually use ChatGPT or Gemini, ask them to "analyze my way of thinking and values from past conversation history" and add that output to make it even thicker.
The answer when you consult this notebook about a problem is completely different from ChatGPT. A life consultation with ChatGPT returns generalities of the world. Correct, but answers that apply to anyone. The Self-Notebook answers based on "your records."
"Doesn't that choice contradict what you said before about 'wanting to prioritize family time'?"
—Being admonished by your own words. This experience is quite a shock.
Career consultation, organizing goals, bouncing ideas when lost. The AI that knows you best in the world is not a ready-made product, but the one you grew yourself. I have been helped by this Self-Notebook every time I had to make an important decision.
2nd Notebook: Boss-Notebook—"Proposals that pass" can be made with preparation
Next is your boss. A "Boss-Notebook" that stores feedback you received, reasons for rejection, and records of projects that got the OK.
What do you use it for? Pre-checking reports and proposals. Before submitting a plan to your boss, ask the notebook this:
"Looking at the boss's past judgments, what parts of this plan are likely to be questioned?"
—What comes back is not a general Q&A. It's a real point of contention based on your boss's actual judgment criteria, like "This boss always asks for evidence of cost-effectiveness. The last rejection was because this part was vague."
Please don't misunderstand; this is not a way to manipulate your boss, but to understand your boss. Your boss's feedback has consistent criteria unique to them. Learn that from records and respond in advance.
As a result, reports pass smoothly, and trust with your boss deepens. Behind the person who "recently started getting their work approved" is this notebook.
3rd Notebook: CEO-Notebook (Company Notebook)—Even juniors can think with a management perspective
Finally, the largest-scale notebook. A "CEO-Notebook (Company Notebook)" that stores the CEO's messages, management policies, company philosophy, and this term's key themes.
What happens when you have this? When you create a plan, you can check with the AI if it aligns with the company's policy.
"Where does this plan align with this term's policy?" "From the CEO's perspective, what are the weaknesses of this proposal?"
—It goes without saying which will pass: a plan made on a whim or a plan that takes policy into account.
And I like another effect. Interacting with this notebook naturally builds the habit of thinking with a management perspective. "What is the company aiming for, and where does this job fit within that?"
Normally, you only see this view after your rank goes up, but you can peek at it through the notebook even as a junior. More than a technique for promotion, I think it's a notebook that makes work more interesting.
From Material Expert to People Understander
When you have the three "people notebooks"—Self, Boss, and Company—your Gemini Notebook becomes both a material expert and a staff officer who understands the entire world you work in. Thinking with your own axis, refining it into a form that passes the boss, and connecting it with the company's policy—all three stages of thinking can be done inside the notebook.
I repeat, you don't need special data. 10 minutes of recording, notes on feedback, policy materials distributed internally. Just store what you already have. This is why I call this usage "my top recommendation."
Chapter 5: My Story—Where an AI lover arrived after 4 years
I've been talking about tools all this time. Now, let me talk a little bit about myself. Why I am so in love with this tool. The reason.
4 years ago, I met ChatGPT and AI became my hobby
I got hooked on AI four years ago. It was my encounter with ChatGPT.
It answered anything I asked, and text was finished in seconds. I was moved every night I touched it, and before I knew it, AI was my complete hobby. And naturally, I thought, "Wouldn't this be the strongest thing if I could use it for work?"
My way of working back then was terrible. I'd arrive at the office at 8 AM and spend an hour replying to emails. The morning would vanish with two meetings and minutes. In the afternoon, I'd struggle with PowerPoint, and finally, in the evening, I'd get to my actual work—but by then, my brain wasn't working.
Overtime exceeded 100 hours a month, and there were nights I missed the last train. I couldn't get home while my children were awake. My wife said, "You're not home much lately," and I couldn't say anything back. I wanted to break this mountain of tasks with the AI I loved. I truly felt that way.
But there was the wall of "I can't put company information in"
However, when I tried to use it for work, I hit a wall.
I couldn't put company information into the AI. Almost all work tasks are paired with company information. Minutes need the content of the meeting. Proposals need customer information. But putting internal information directly into an external AI is scary for security and bad for rules.
So I was converting information into test data every time. Replacing customer names with "Company A," making numbers dummy data, and then converting the answers back to real information.
...Do you see? Time was melting away in the preparation to have the AI save time. A complete contradiction. Plus, there was the problem of "plausible lies" I mentioned in Chapter 2. AI is amazing. But it couldn't step into the heart of work. Because I loved AI, I felt this frustration more than anyone.
The encounter was in the company's Google Workspace
The tool that broke that wall was inside the Google Workspace we used at the company. NotebookLM—now Gemini Notebook.
After touching it for a few days, I was convinced. There is no AI with better compatibility for work than this. It is designed with the premise of putting company information in. It only answers with the materials you put in, so it doesn't lie. Answers come with evidence. This was the "last piece" I had been searching for for four years.
The first thing I assigned it was minutes. I still remember how I felt when I saw the minutes completed five minutes after putting in the recording and asking for them. From there, I just practiced what I wrote in Chapter 3 of this article one by one.
Emails, reading materials, creating materials, inquiry desks, learning, Self-Notebook. Every time I assigned one, the view in the evening changed.
What changed was the use of time—in other words, life
Before I knew it, I was able to go home on time.
I get home while my children are awake. We eat together, take a bath, and I put them to bed. Being able to do the obvious things obviously. How luxurious that was. The day my wife said, "You're home lately," I was honestly almost in tears.
The time I got back also returned to me. In one hour at night, I started sharing effective ways to use it on X, and as a result of continuing steadily every day, I have over 50,000 followers, got opportunities to speak, and even published a book. It completely exceeds the imagination of the man who was touching ChatGPT as a hobby in the middle of the night four years ago.
But please don't misunderstand. I haven't done anything special. What changed was not my ability, but how I use my time. I left the tasks to the AI and poured the free time into my family and my own future.
That's all. Gemini Notebook is not a magic wand, but a proper tool for changing where you place your time. That's why anyone can reproduce it. That's why I'm writing this article so seriously.
Chapter 6: How to start in 15 minutes today
I've talked enough about the charm. All that's left is for you to touch it. I'll lead you through the first 15 minutes.
1. Open (2 minutes)
—Search for "Gemini Notebook" (you can also find it by its old name "NotebookLM") in your browser and log in with your Google account. No installation or payment required.
2. Create a box (1 minute)
—Create one notebook with "New." A name like "My First Notebook" is enough.
3. Put in one document (5 minutes)
—Just one work document you have on hand. I recommend "a document you've left alone thinking you should read it." Manuals, reports, minutes, anything. (Start with something low-confidentiality. Don't forget to check business use rules.)
4. Ask a question (7 minutes)
—Type this into the chat:
Please tell me the 5 main points of this material so that even someone reading it for the first time can understand. Please also indicate where in the material each point is written.
After a few dozen seconds, an answer with citations will return. Click the numbers in the answer and jump to the original text. —You, becoming detailed on a document you haven't read. This 15-minute experience is the entrance to all the charms I've talked about in this article.
Summary: Your librarian, not a know-it-all
Thank you for reading this long article to the end. I'll compress everything into three lines.
Gemini Notebook is an AI that becomes an expert on the materials you give it. It doesn't lie, answers come with evidence, it gets smarter the more you store, materials transform into radio, maps, or slides, and it's free and safely designed for work use. —Not a know-it-all for the whole world (ChatGPT), but your personal librarian. This is the one you should choose as your work partner.
In this article, I've talked about the charm "thoroughly." But to be honest, this is as far as I can convey with text. The feeling of minutes coming out in 5 minutes. The trust when it honestly says, "That information is not in the materials." The laughter when your own materials turn into a radio stream. —The core of the charm is in your first 15 minutes.
To you, who feels like "AI is amazing but I'm not using it fully at work," just like I did four years ago. The last piece you were looking for is probably this. Give it 15 minutes today.
The AI world evolves really fast. Rather than trying to keep up with the latest information alone, following someone who practices and shares every day is the most certain and fastest way.
▼ Follow me on X (Twitter) here
On my account, I share tips every day on how to accelerate work efficiency and time-saving with AI. I share more details than anyone else on how to use NotebookLM, so if you want to master the latest AI, please follow me! @ai_jitan
**
【Free OpenChat Started 🔥】
Exclusively in the OpenChat, I will also give away:
- 600 Selected Prompts for NotebookLM (Illustrated version)
- 20 Selected GPTs & 20 Selected Prompts 🎁
Beginners and those who just want to watch are also welcome 🙌 First, feel free to take a peek 👇
**
Announcement of the release of the book "AI Work Fastest Encyclopedia: NotebookLM Ready-to-Use Skills"
I've packed all the NotebookLM skills that changed my life into one book. Released on July 16th (Tue). And I've prepared serious bonuses for those who purchase.
I will directly explain the NotebookLM utilization techniques packed in the book. I've made the content so you can learn together with the book next to you once it arrives.
【3 Major Bonuses for All Purchasers】
- 1. NotebookLM Prompt Collection (Super-sized version)
- 2. Business-Specific Gems (30 selected + α)
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▼ Purchase here
https://x.com/ai_jitan/status/2060255422666465649
The bonus seminar is basically for those who pre-order by the release date (7/16) (for the Kindle version, applications up to the day of the seminar will be valid).
▼ Purchase here 👇
