This tutorial treats object-oriented concurrent programming (OOCP) as the natural generalization of object-oriented programming. OOCP decomposes a large program into a collection of small modules that run and interact concurrently and are capable of exploiting parallel hardware. The tutorial describes various levels of integration between object-oriented programming and concurrency, leading to the notion of an active object, which unifies object and activity, message passing and synchronization. The tutorial introduces Concurrent Smalltalk to describe concepts, constructs, and methodology. Examples include programming with continuations, divide and conquer, and pipelining. It also shows how to implement active objects, and uses Actalk as an example. Finally, it compares various OOP models and languages, with a special focus on the Actor computation model. Although the tutorial uses Smalltalk for examples, you dont need to know Smalltalk to understand it; a quick introduction to Smalltalk syntax is included. It assumes that you understand object-oriented programming well, but little more about concurrency than intuitive concepts of processes and synchronization.