Learn You a Haskell For Great Good (http://learnyouahaskell.com/ http://learnyouahaskell.com/). Despite Haskell's reputation for its difficultly due to its stri

Learn You a Haskell For Great Good (http://learnyouahaskell.com/ http://learnyouahaskell.com/). Despite Haskell's reputation for its difficultly due to its strictness and fundamental differences with mainstream imperative languages, the book manages to smoothly introduce the purely functional paradigm with tons of effective and concise examples. The book ends just where the infamous Monad is introduced and doesn't touch any of deeper capabilities of Haskell's type system, but still serves as a wonderful introduction to the language and pure functional programming. A lot of people mention SICP as the book that made them rethink/rediscover computer science, for me this book had the same effect.