Google's NotebookLM gets a major upgrade with Deep Research, a feature that allows the AI to browse hundreds of websites and create detailed reports with annotated source lists. This is a significant improvement from earlier versions, which were limited to text files and PDFs. With Deep Research, users can enter a topic, select 'Web' as their source, and choose between 'Fast Research' for quick summaries or 'Deep Research' for in-depth insights. The tool then crafts a research plan and scours the web to refine its search, adding a comprehensive report to the user's notebook. This feature is expected to reach all users within a week, with some regional variations in availability. Additionally, Google has expanded NotebookLM's source compatibility, allowing users to upload Google Sheets, Microsoft Word drafts, and PDFs from Google Drive, as well as images of handwritten notes or brochures. This enhancement streamlines the research process, saving users time and effort. Furthermore, NotebookLM now offers custom video overview styles and a chat history prompt, enabling users to create personalized video summaries and seamlessly resume research sessions without losing previous content. These updates collectively make NotebookLM an even more powerful research assistant, revolutionizing the way users gather information and conduct academic research.