concurrency is the art of making computer do (or appear to domultiple things at once historicallythis meant inviting the processor to switch between different tasks many times per second in modern systemsit can also literally mean doing two or more things simultaneously on separate processor cores concurrency is not inherently an object-oriented topicbut python' concurrent systems are built on top of the object-oriented constructs we've covered throughout the book this will introduce you to the following topicsthreads multiprocessing futures asyncio concurrency is complicated the basic concepts are fairly simplebut the bugs that can occur are notoriously difficult to track down howeverfor many projectsconcurrency is the only way to get the performance we need imagine if web server couldn' respond to user' request until the previous one was completedwe won' be going into all the details of just how hard it is (another full book would be requiredbut we'll see how to do basic concurrency in pythonand some of the most common pitfalls to avoid