When you feed an entire book to an LLM (Claude specifically), what prompts are most effective at getting it to do a good and insightful summary?

I want it to read the book and report, not rehash a goodreads/wikipedia entry on the same. Since things like Claude and Gemini have large token limits, it feels like an opportunity to get them to do some reading for me.

"Summarise this book" doesn't yield results with depth and the answers can feel as good as the usual Google/Goodreads snippet.