This is the early edition of the book. See also the reworked edition published by Manning Publications ("Functional Design and Architecture: Examples in Haskell).
The book focuses on design patterns, best practices, and approaches to creating applications using pure functional languages such as Haskell. It aims to consolidate all the knowledge about how to create big applications in a pure functional manner. This area is not yet well covered, but the community has invented many approaches, and we need to make a comprehensive source of knowledge as it was done for Object-Oriented Programming already.