"For over a decade prophets have voiced the contention that the organization of a single computer has reached its limits and that truly significant advances can be made only by interconnection of a multiplicity of computers."

--Gene Amdahl, 1967

Although the discipline of concurrent programming has a long history, it gained a lot of traction in recent years with the arrival of multicore processors. The recent development in computer hardware not only revived some classical concurrency techniques, but also started a major paradigm shift in concurrent programming. At a time, when concurrency is becoming so important, an understanding of concurrent programming is an essential skill for every software developer.

This chapter explains the basics of concurrent computing and presents some Scala preliminaries required for this book. Specifically, it does the following:

• Shows a brief overview of concurrent programming
• Studies the advantages of using Scala when it comes to concurrency
• Covers the Scala preliminaries required for reading this book

We will start by examining what concurrent programming is and why it is important.