There are a million monad tutorials for Haskell (and, with respect to their use in Haskell, it's probably better to learn them from there). I think that a good

There are a million monad tutorials for Haskell (and, with respect to their use in Haskell, it's probably better to learn them from there). I think that a good one is "You Could Have Invented Monads!". This[1] is a good paper about monads in functional programming. It reads quite similarly to a monad tutorial, but with a little more formality. As for actual category theory, I've enjoyed the first few chapters of "Algebra: Chapter 0", by Aluffi. If you're after more type theory, the usual recommendations are "Types and Programming Languages", by Pierce, and "Software Foundations", also by Pierce. [1] http://homepages.inf.ed.ac.uk/wadler/papers/marktoberdorf/baastad.pdf http://homepages.inf.ed.ac.uk/wadler/papers/marktoberdorf/ba...