- Coursera mooc on Programming Languages aims to introduce students to functional programming.
- Structure and Interpretation Of Computer Programs by Abelson, Sussman, and Sussman: This free online book is the companion to the famous Abelson and Sussman SICP lectures at MIT from the 1980s onward, which are also available as videos. Similar course is CS61A at Berkely.
- Functional Programming For The Rest Of Us: an informal introduction to FP for people who know a bit about regular (imperative) programming but are new to FP, with examples.
- Simple Made Easy talk by Rich Hickey (author of the Clojure language).
Lisp and Haskell : These are two “pure” FP languages.
- Real World Haskell – free online version of the book this is a hands-on book: every chapter contains dozens of code samples.
- Practical Common Lisp – online edition of the 2005 book by Peter Seibel (Apress).
- Learn You A Haskell For Great Good – free online version of the book by Miran Lipovaca.
- The Nature Of Lisp – another interesting article from Slava Akhmechet
Functional programming on the JVM with Scala and Clojure: Clojure is an implementation of Lisp on the JVM, so it is functional and not object-oriented, while Scala is a functional programming language that is also object-oriented.