Google NotebookLM is an experimental tool developed by Google Labs that uses AI, specifically the Google Gemini model, to assist users in interacting with their documents. It can generate summaries, explanations, and answers based on uploaded content, including Google Docs, PDFs, websites, and Google Slides. It also offers features like "Audio Overviews" and allows users to create and organize notes independently, making it a virtual research assistant that facilitates efficient note-taking and analysis.