Hello everyone. I just found this forum in my searches for ways to make my iBooks better. I just published a textbook called "The Electric Force." It's in the textbook section (science) as well as the book section (science/physics). It was a great experience creating the book. Apple is way ahead of the competition when it comes to creating tools for book creators. There's nothing comparable to iBooks Author for Kindle books or any others.
Take a look at the book, the sample is free and it's a whole chapter in the book so you can get a good feel for the book for free.