An easy to read book and a great way to get up-to-speed on Clojure.
Clojure in Action is a hands-on tutorial for the working programmer who has written code in a language like Java or Ruby, but has no prior experience with Lisp. It teaches Clojure from the basics to advanced topics using practical, real-world application examples. Blow through the theory and dive into practical matters like unit-testing and environment set-up, all the way through building a scalable web-application using domain-specific languages, Hadoop, HBase, and RabbitMQ.
Clojure is a modern Lisp for the JVM, and it has the strengths you'd expect: first-class functions, macros, support for functional programming, and a Lisp-like, clean programming style.
Clojure in Action is a practical guide focused on applying Clojure to practical programming challenges. You'll start with a language tutorial written for readers who already know OOP. Then, you'll dive into the use cases where Clojure really shines: state management, safe concurrency and multicore programming, first-class code generation, and Java interop. In each chapter, you'll first explore the unique characteristics of a problem area and then discover how to tackle them using Clojure. Along the way, you'll explore practical matters like architecture, unit testing, and set-up as you build a scalable web application that includes custom DSLs, Hadoop, HBase, and RabbitMQ.
This book assumes you're familiar with an OO language like Java, C#, or C++ but requires no background in Lisp or Clojure itself.