Google has launched “Deep Research”, a new feature in its AI note-taking assistant NotebookLM, designed to automate online research and generate detailed, well-sourced reports. The tool aims to simplify complex research tasks while supporting additional file types such as PDFs, Google Sheets, and Word documents.
Since its launch in late 2023, NotebookLM has evolved into a powerful AI research assistant. Earlier updates included Video Overviews and Audio Overviews, enabling users to transform complex notes, multimedia files, and legal or educational documents into concise, digestible formats. Dedicated Android and iOS apps were introduced in May 2025, expanding accessibility beyond desktops.
Deep Research functions as a virtual research assistant, capable of:
“Deep Research allows users to build a comprehensive knowledge base on a topic without interrupting their workflow,” said a Google spokesperson.
Users can initiate Deep Research by selecting “Web” as the source in the NotebookLM panel and choosing between Deep Research for thorough analysis or Fast Research for quicker searches.
Multi-file support now includes:
This allows users to generate summaries or extract data efficiently across different file formats.
While Deep Research works in the background, users can continue to add other sources or notes simultaneously, ensuring seamless workflow integration.
Google confirms the update will roll out to all users within a week, reinforcing NotebookLM’s role as a comprehensive AI research and note-taking platform.