This is the 4th edition of a successful book which first appeared in 1982. It is an introduction to programming in general as well as a manual for programming with the language Modula-2 in particular. It is oriented primarily towards people who have already acquired some basic knowledge of programming and would like to deepen their understanding in a more structured way. Nevertheless, an introductory chapter is included for the benefit of the beginner, displaying in a concise form some of the fundamental concepts of computers and their programming. The text is therefore also suitable as a self-contained tutorial. The notation used is Modula-2, which lends itself well to a structured approach and leads the student to a working style that has generally become known under the title of structured programming. Modula-2 is a descendant of Pascal, and is particularly suited for programming larger and more complex systems in a structured way. The principal improvement in this 4th edition is a completely new layout. The main changes in the contents are a few minor adaptations in the area of type compatibility. "Programming in Modula-2" by Niklaus Wirth can be considered as the standard reference for Modula-2 programmers.