The quickest way to start reading right now is to view the PDF version here:
https://github.com/thoughtbot/ios-on-rails/raw/master/release/ios-on-rails.pdf
The book is currently available in the following formats:
- PDF: release/ios-on-rails.pdf
- Single-page HTML: release/ios-on-rails.html
- Epub (iPad, Nook): release/ios-on-rails.epub
- Mobi (Kindle): release/ios-on-rails.mobi
For the HTML version, clone the repository and look at the HTML so that images and other assets are properly loaded.