This book is written for This book is a "language reference", and it is not intended for complete beginners.
Do you find Haskell difficult?
If so, that's probably not because functional programming is inherently more difficult. Haskell, which is by far the most widely used pure functional programming language, uses syntax that is rather different from that of the more traditional C-style programming languages. This book provides the best summary of the essential grammar of the modern Haskell programming language (Haskell2010), both syntax and semantics.
Although it is written as a reference, you can read it more or less from beginning to end and you should be able to get the overall picture of the Haskell language if you have some prior experience with functional programming in Haskell or other ML-style functional programming languages. Once you go through this book, you will find functional programming much easier. This book is, however, not for absolute beginners.
The book covers Order your copy and learn Haskell today!