As we said at the very beginning, this manual is not intended as a tutorial on either functional programming in general, or Haskell in particular. For these things, our first recommendations would be for the Introduction to Functional Programming by Bird and Wadler [4], and the Gentle Introduction to Haskell by Hudak, Peterson and Fasel [5], respectively. Note, however, that there are several other good textbooks dealing either with Haskell or related languages.

For those with an interest in the implementation of Hugs, the report about the implementation of Gofer [6], Hugs' predecessor, should be a useful starting point.

Further reading