Gemini Notebook (the product everyone still calls NotebookLM) is the best free research notebook in the market: grounded in *your* sources, Audio Overviews that actually help, and a July 2026 rename plus a notebook.google.com URL that old links follow. The free tier is enough to run a serious personal knowledge base. Google AI Pro ($19.99/mo) and Ultra raise source/notebook limits and unlock the in-notebook code runtime. Use it when the job is 'answer only from this pile of PDFs,' not as a general chatbot. It will not replace Claude or ChatGPT for open-ended writing. For students, consultants, and operators drowning in decks, it is one of the highest-leverage free tools in this catalog.
Gemini Notebook is Google's standalone research assistant, renamed from NotebookLM in July 2026. Upload docs, slides, PDFs, URLs, and YouTube videos; chat only against those sources; and generate Audio Overviews, study guides, and (on paid plans) code-backed analysis. Lives at notebook.google.com; old NotebookLM links redirect.