Who would this be for? It feels very introductory but haskell is unlikely to be one of your first programming languages[1]?

The same author wrote a very popular book about category theory that introduces Haskell in a way i’d think most developers would find more tractable.

[1] there’s exceptions of course, at UofG they threw Haskell at us right after Ada back in at the turn of the millennium. That’s an interesting trajectory for course design, first lang is ada and second is haskell