NotebookLM is Google's source-grounded AI research assistant: users upload their own documents, and it answers questions, generates study materials, and produces "Audio Overviews" (AI-generated two-host podcast-style discussions of the material) and "Video Overviews," using only the uploaded sources as its knowledge base — reducing hallucination risk compared to open-ended chat. On July 16, 2026, Google renamed the product "Gemini Notebook" as part of a broader consolidation of its AI products under the Gemini brand, and added the ability to run code directly within notebooks for deeper data analysis. It's not sold as a standalone subscription; access is bundled into Google's AI plans: Standard/Free ($0 — 100 notebooks, 50 sources/notebook, 50 daily chats, 3 Audio/Video Overviews per day), Plus (via Google AI Plus, ~$4.99/month), Pro (via Google AI Pro, ~$19.99/month — 500 notebooks, 300 sources/notebook, 500 daily chats, 20 Deep Research reports/day), and Ultra (via Google AI Ultra, $99.99–$199.99/month). It's also included in Google Workspace Business Standard and above, and syncs bidirectionally with the main Gemini app.