This book is for you if you’ve got some programming experience and if you’re not too familiar with functional programming. It can still be useful if you’re too good for that, as we progressively go into more and more advanced topics.

The book started as a free online guide, and you can still read it that way. If you prefer the soft touch of paper, the delicious smell of a real book, the possibility to physically hug a document, or just want to boast by padding your bookcase, you can buy a few copies too (and e-books are also available).