If you don't like the look or layout of your book, you can easily re-arrange it using the Book Navigator including the possibility of adding a cover and table of contents. You can also add a voice-over to make it easier for sight-impaired readers to read your books. They enable you to add everything from a photo gallery to a Keynote (Keynote ’09 v5.1.1 or later) presentation and can be easily identified in your Table of Contents.
The widgets are one of the outstanding features of iBooks Author.
