Grand Central Dispatch (GCD) is a technology that provides a high-level API for safely dealing with concurrency and leveraging multicore architectures. With Dispatch, you don't need to deal with threads and thread pools anymore; instead, you'll work with operations and queues.
Using GCD, you'll be able to write efficient, multitasking code that scales from few to many CPU cores. Let's begin with the basic concepts of queues and tasks; then we'll cover the different techniques for synchronizing tasks.
