We have to distinguish learning from, let's call it, recreational education. If you're learning a topic, you're not going to be using a single book. Not even schoolchildren do that. Regardless of whether you consider a book an authoritative source, if you read multiple books those books will have to agree with each other, and where they don't you'll experience some confusion until you can resolve the contradiction.

If you're only ingesting information from a single source, be that a book, a teacher, or an LLM, then you haven't really learned, because your knowledge base is unmoored. You can't learn history by studying Tolkien's mythos.