Learn You a Haskell for Great Good!
Learn You a Haskell (LYAH) is the friendly, illustrated, free online Haskell introduction that a lot of people start with. I read it as the third track in my Haskell study, alongside The Haskell Book for the deep theory and laws and Haskell by Example for project-driven practice, and I own it in print, mostly to support the author. LYAH ended up being my “medium” book. It wasn’t demanding enough to need my protected morning focus time, but it wasn’t throwaway reading either. It moves fast and covers an enormous amount of ground in relatively few pages, and it rarely gives you exercises, so it was easy to pick up between chapters of my heavier books, but I also retained less from it than from the books where I was typing and testing code. More than once I described it as a book where you’re lucky to keep anything, but you’ll recognize the topic when it comes up again somewhere else, and that turned out to be worth a lot, since plenty of concepts were already familiar by the time The Haskell Book covered them properly. ...