Concurrency is everywhere. With the rise of multicore processors in the consumer market, the need for concurrent programming has overwhelmed the developer world. Where it once served to express asynchrony in programs and computer systems, and was largely an academic discipline, concurrent programming is now a pervasive methodology in software development. As a result, advanced concurrency frameworks and libraries are sprouting at an amazing rate. Recent years have witnessed a renaissance in the field of concurrent computing.

As the level of abstraction grows in modern languages and concurrency frameworks, it is becoming crucial to know how and when to use them. Having a good grasp of the classical concurrency and synchronization primitives, such as threads, locks, and monitors, is no longer sufficient. High-level concurrency frameworks, which solve many issues of traditional concurrency and are tailored towards specific tasks, are gradually overtaking the world of concurrent programming.

This book describes high-level concurrent programming in Scala. It presents detailed explanations of various concurrency topics and covers the basic theory of concurrent programming. Simultaneously, it describes modern concurrency frameworks, shows their detailed semantics, and teaches you how to use them. Its goal is to introduce important concurrency abstractions, and at the same time show how they work in real code.

We are convinced that, by reading this book, you will gain both a solid theoretical understanding of concurrent programming, and develop a set of useful practical skills that are required to write correct and efficient concurrent programs. These skills are the first steps toward becoming a modern concurrency expert.

We hope that you will have as much fun reading this book as we did writing it.