If you have a presentation you've given more than once, you already have your book.
You've tested your framework with real audiences. You know which stories land. You know which examples make people lean forward. You know the exact questions people ask afterward.
That's a finished product sitting in your head. You just need to get it on the page.
Here's the opportunity: Your presentation reaches the room. Your book reaches them long after they leave, as well as everyone who wasn't there.
Same content. Same framework. Completely different scale.