Can I review and edit the outline before the book is written?

Yes. In the New Book wizard, on the "Structure" step, enable "Review the outline first".

Generation pauses after the outline: on the book's page you can edit every chapter title and its beats, reorder chapters, add or remove chapters, or type an instruction for the AI (e.g. "make chapter 3 focus more on habits") and let it revise the outline.

When you're happy, click "Approve & write the book" — the chapters are written from exactly the outline you approved.