I don't think that RWH is at the same level of SICP and the other masterpieces of programming language theory: CTM and TAoP (The Art of Prolog).

RWH is just a good Haskell book teaching people how to do practical things with the language, but it doesn't have the intention of reaching the level of conceptualism and abstraction that the books I've mentioned achieve.

In fact, I think that RWH is not a good book for learning Haskell unless you're a Java programmer. It's mainly written for that audience. In case you come from Lisp or even Ruby or Python I'd strongly recommend A Gentle Introduction to Haskell (http://www.haskell.org/tutorial/).

It's been the officious Haskell tutorial since 1998. It's short, free and written by very relevant members of the Haskell community.

RWH is great too, but the topics are very different. RWH is about using functional programming. CTM is about a lot of different paradigms. It starts with a simple core language, and a set of features, like dataflow variables, lazy evaluation, higher order functions, concurrency, ports (message passing queues), mutable state, backtracking. Then it explores what happens if you take a subset of these features. For example dataflow variables + concurrency is deterministic concurrency. Mutable state + higher order functions can support object oriented programming. Ports + concurrency is an Erlang like model.

Lazy functional programming is just one of these models (higher order functions + laziness). CTM shows that other models can be beautiful and powerful too.

Could you tell us why?