I'm bouncing between that book and "The Haskell School of Expression"( http://www.haskell.org/soe/ ). The second seems to be better at describing data structures and building the language in your mind while the first is more of a reference of useful ideas.

It's strange how I never heard of this one, while the other gets a lot of attention. Is it very outdated?

I had a lot of trouble trying to get the libraries they mentioned working. The code examples in the book are so straight forward it was simple to implement them in OpenGL. I have not run across wrong information yet.

On a side note, I went to the Boston Haskell Users Group and their advice was "just read the Haskell Report". I needed a little more gentle introduction before we go jumping into the deep end of the pool.