NotebookLM is back with two new features to simplify online research. The “Deep Research” option helps you find high-quality sources for in-depth analysis, while the existing “Fast Research” option is now called “Discover”. You can add reports and sources used to your notebook. Additionally, NotebookLM supports more file types, including Google Drive files and Microsoft Word documents. These new features will be available to all users within a week.
Source: https://9to5google.com/2025/11/13/notebooklm-deep-research