Updated 11/13/25: 

NotebookLM Adds Deep Research and Support for More Source Types

Google announced Deep Research in NotebookLM, alongside new support for Google Sheets, images, Word documents, and PDFs from Google Drive. Give it any topic and it automatically gathers sources, writes a research report, then lets you import those sources to explore with chat, mind maps, and audio overviews. NotebookLM also now turns your research documents and notes into customizable video overviews by letting you describe the style you want in a simple prompt.