Beginner
- Official language guide by Swift.org
- Video course “iOS 12 app development bootcamp” @Udemy by Angela Yu
- Video “Introduction to Swift” @Apple WWDC 2014, by Tim Isted and Dave Addey
Intermediate
- Book “Swifter - Swift Must Know Tips (in Chinese)" by Wei Wang
- Book “Swift実践入門 (in Japanese)" by 石川洋資，西山勇世
- Book “詳解Swift (in Japanese)" by 荻原剛志
- Video “Protocol-Oriented Programming in Swift” @Apple WWDC 2015, by Dave Abrahams
- Video “Building Better Apps with Value Types in Swift” @Apple WWDC 2015, by Doug Gregor and Bill Dudney
- Book “Design Patterns by Tutorials” by Joshua Greene and Jay Strawn
- Book “Data Structures and Algorithms in Swift” by Kelvin Lau and Vincent Ngo
Advanced
- Video series “Swift Talk” @objc.io
- Book “Advanced Swift” by Chris Eidhof, Ole Begemann, and Airspeed Velocity
- Book “Functional Swift” by Chris Eidhof, Florian Kugler, and Wouter Swierstra
- Book “App Architecture” by Chris Eidhof, Matt Gallagher, and Florian Kugler