EDIT: Link is live now. Here is the link to the online documentation if you don't want to download it on iBooks. https://developer.apple.com/library/ios/welco

EDIT: Link is live now. Here is the link to the online documentation if you don't want to download it on iBooks. https://developer.apple.com/library/ios/welcome_to_swift https://developer.apple.com/library/ios/welcome_to_swift