iBooks Author
Naturally, once your text is in iBooks Author, you’re essentially writing and editing within a page-layout application, rather than a word processor or text editor. As with any publishing workflow, you will want to do the writing and editing first, and then put the book together (as much as possible). iBooks Author is resolutely not a writing environment.
iPad-exclusivity aside, those willing to work in iBooks Author should be quite pleased. It’s the best WYSIWYG ebook designer I’ve seen on the market so far, and—formatting problems excluded—incredibly easy to work with.