The Joy of Clojure: Thinking the Clojure Way [Brossura]

As of right now, there are 3 Clojure books available in full (Programming Clojure, Practical Clojure, and this one), and one on the way (Clojure in Action). I can't speak to Clojure In Action, but I've read the first 3, and this is definitely the best one.

1) It covers Clojure 1.2, which is the current version, and has some important differences from 1.0 and 1.1. The new features are pretty cool, but sometimes their purpose is a bit obscure when looking through the documentation.

2) It's so darn specific, while at the same time being very concise. Common sticking points, like the behavior of unquote splicing, are gone over with non-trivial but easily understandable examples. Structural concerns like refs vs agents vs futures vs promises are discussed with good explanations for when you should use each.

3) It explains why things are cool - for instance the explanation of "state" and "identity" in functional programming is one of the best I've seen. If only there was a section on monads, this book would be downright canonical.

Basically, if you're planning on writing Clojure, or you want to see if the language jibes for you, you should get this book.

Clojure is a language that makes many unique language design decisions. In order to appreciate the thinking behind these decisions, you will need to get good understanding of the Clojure philosophy. Chris and Fogus understand this philosophy like the back of their hands and reading "The Joy of Clojure" is possibly the fastest way to get up to speed with this exciting and powerful new Lisp dialect.

This book covers all the basics you need to know to get started with Clojure: It begins with a thorough explanation of the Clojure syntax and explains how to find your way around "functional programming", a key concept you'll need to be comfortable with to use Clojure effectively. These concepts are all explained with clear examples and with every new command and concept the authors also cover "big picture" topics that help the reader understand the importance of each item and help cement them into the reader's memory.

The second half of the book focuses on the pragmatic and advanced topics of the language. In terms of pragmatic topics, you will find detailed descriptions on how to interact with Java (very easy in Clojure) and use this to build a UI app. The authors also cover optimization and the static typing abilities of Clojure in great detail.

Another advance topic that "Joy of Clojure" has extensive coverage of is Clojure's insanely powerful multithreaded programming features. Here, you will learn why Clojure's solution to the "multithreaded programming dilemma" might be the best way to write bug-free code that can make full use of a multicore processor. The authors do a great job explaining the "whys" and "hows" of multithreaded programming and tell you everything you need to know to get the performance want out of your processor's cores.

Chris and Fogus live and breathe Clojure code and are part of the core Clojure community. What you're paying for when you buy this book is an introduction to the language from people who really understand what's important and what it takes to write efficient and idiomatic Clojure code. If you're interested in learning Clojure, I suggest you first look at the great videos on youtube from Rich Hickey, the language's creator. After that, I recommend you pick up "Joy of Clojure" and you'll be a fully capable Clojure developer in no time.

(Disclosure: Fogus reviewed a book I wrote last year called "Land of Lisp".)

In the realm of technical, programming-related, computer science-type books, The Joy of Clojure is a bit of an oddity. And this is a very good thing.

WHAT THE BOOK IS NOT: The Joy of Clojure is not a beginner's introduction to the language. The Joy of Clojure is not a glorified appendix of methods and syntax. The Joy of Clojure is not a "cookbook" or a "how-to" or an "FAQ". The Joy of Clojure is not an explanation on how to shoe-horn your Java code into (some (graceful [parenthetical syntax])). The Joy of Clojure is not a dry or sterile technical manual.

WHAT THE BOOK IS: The Joy of Clojure is as much a philosophical text as it is a survey of the language. The Joy of Clojure embraces the language's own flexible nature and describes itself in that way. The Joy of Clojure has a sense of humor. The Joy of Clojure expects a little work from you (but is willing to lend a hand along the way). The Joy of Clojure respects the baggage that you bring from your other programming languages, but expects you to check those bags at the door. The Joy of Clojure wants to make you a better programmer, not a Clojure programmer.

I would absolutely recommend this to anyone I know that had an interest in Clojure and/or functional programming.