The book offers a compact introduction to the concepts of object-oriented programming. It explains the concepts of objects and classes, describes encapsulation techniques, and goes into detail about subtyping and inheritance. Software reuse in the form of library components and program frameworks is addressed through the example of stream processing and the construction of graphical user interfaces. Additionally, important concepts of parallel and distributed programming are discussed, establishing a practical connection to object orientation. Each object-oriented concept is introduced independently of a programming language, followed by an explanation of its concrete implementation in Java. Some implementation variants in other object-oriented languages are also presented. From a practical perspective, this results in an overall comprehensive understanding.