iBooks Author Beginner and User Guides
You can download the free iBooks Author Application from Apple here.
The blog post How To Publish An eBook With iBooks Author Tutorial gives you a phenomenal overview of iBooks Author and the key features and options.
O'Reilly Media has produced an amazing 110 page free guide called Publishing with iBooks Author to help you get up and writing with iBooks Author.
Arstechnica writes an article that reviews iBooks Author and the whole iBook publishing experience.
Apple explains that iBooks Author isn't just for education - and how you can take your business content from standard to stunning on this page.
This iBooks Author Pinterest Board has everything you need and is updated regularly.
iBooks Author How-To Tutorials and Videos
Emerson College Department of Journalism has produced over 20 short video tutorials to get you up and writing with iBooks Author quickly.
This hour long video explains How to Create and Distribute iBooks in Education.
iBooks Author Themes has a great 2 part video series on how to design, create, and customize your own template from scratch.
The Bookry has over 25 more advanced video tutorials to check out here.
iBooks Author Templates
3rd Party Widgets & Services
Using Tumult Hype, you can create beautiful custom HTML5 widgets for your book (no coding required).
Check out Class Widgets for both free and paid widgets.