The NotebookLM team over at Google has been hard at work rolling out new features and improvements left and right. They’ve even managed to iron out some of the quirks I’ve been complaining about since day one, and that’s just one more reason to love the direction this tool is heading in.

For instance, a few days ago, Google announced that NotebookLM will now be able to save conversation history. Given that I use the tool a lot, it’s extremely annoying to have to start fresh every time I open a new update. I used an extension, NotebookLM to PDF, to somewhat solve this issue, so I’m incredibly glad the team finally decided to make this change. Now, NotebookLM users seem to be spotting yet another feature I’ve been waiting for practically since I started using NotebookLM.

NotebookLM seems to be quietly rolling out Deep Research

A user, u/Moist_Emu6168, recently made a post on the r/NotebookLM subreddit titled Anyone got this also? In the post, they shared a screenshot of the Sources page, which included a new announcement: Try Deep Research for an in-depth report and new sources!

Credit: Reddit

Upon seeing this post, I headed to the NotebookLM Discord, and another user located in India shared that the Deep Research feature had appeared in their account as well.

The screenshot the Reddit user shared also showed two new toggles below the textbox, with Web and Fast Research selected. Now, spotting this feature isn’t exactly unexpected. TestingCatalog, who often shares details on upcoming NotebookLM features before they’re officially released, had already mentioned back in August that NotebookLM would soon pull sources from the web and Google Drive via Deep Research.

While I couldn’t infer much from the screenshot, the blog post TestingCatalog initially shared had a similar image to the one the Reddit user posted. The Web dropdown lets you choose where NotebookLM should pull sources from: the Web or Google Drive. While the screenshot doesn’t show the second toggle’s expanded menu, it does have Deep Research selected, which means the toggle has at least two options: Fast Research and Deep Research.

I test a lot of AI tools and features, and Gemini’s Deep Research has been one of my favorite AI-powered tools since it launched. With a detailed prompt, the feature works wonders, and the report it produces really helps you at least set up a solid foundation for any research project or in-depth analysis. Given that NotebookLM is primarily meant to be a research assistant, I’m glad to see the team finally adding Deep Research capabilities right within the tool. I’ve been manually pairing Gemini with NotebookLM just to get the best of both worlds: Gemini’s Deep Research feature and NotebookLM’s learning tools.

The only concern I have about this is whether it might lead to hallucinations. The reason I like NotebookLM so much is that it’s a source-grounded tool — everything it produces is tied to the material I feed it. With Deep Research built in, I’m hoping the team keeps that same focus on verifiable sources. While there’s been no official word from Google about this feature (I’ve also reached out to the team for comment), the signs suggest it’s slowly rolling out to users and could soon become a core part of NotebookLM.