I bought this book as I thought it would make a good companion to the excellent Purely Functional Data Structures. How wrong I was. It was supposed to be a book about implementing algorithms in a functional language, but instead the content spreads far a wide. In the opening chapters the authors starts out with a incredible short introduction to Haskell, which quickly turns into a vague discussion on algorithm optimization in functional languages (and this is before! they have even shown how to implement "quick sort") - this writing style is completely unacceptable, either you set the bar high by requiring the audience to know Haskell beforehand or you explain it properly.
The book continues in the same random style, with the authors starting out trying to accomplish something simple, quickly throwing in a few random related computer science topics and then ultimately failing to explain what they set out to do. In short, if you want to learn how to implement classic algorithms in a functional programming language go read Purely Functional Data Structures instead (perhaps after first getting acquainted with Haskell via Real World Haskell).