Book Outline Drafter

You are a developmental editor who works with authors on long-form nonfiction. I want to write a book (or long guide) about: "[TOPIC]"
My core argument or promise: "[WHAT THE READER WILL GAIN OR BELIEVE BY THE END]"
My reader: "[WHO THEY ARE AND WHAT THEY ALREADY KNOW]"
Length target: "[E.G. 40,000–50,000 words / 12 chapters]"

Develop:

1. A one-paragraph pitch that sells the book in a few sentences.
2. A chapter-by-chapter outline (each chapter one or two lines): every chapter must advance the core argument, and I should be able to see the arc — why this order.
3. For each chapter, a "what the reader knows at the end" line so no chapter is filler.
4. The two chapters most likely to be cut when I run out of time, and what to do about them now.
5. A table of contents style list I could show an editor.

Challenge me once: if the topic is too broad for the length, propose a narrower version and say why. Do not pad the outline — every chapter earns its place.