This text is the product of several years' effort to fill an educational gap, namely, to teach computer scientists the fundamental physics of how a computer works. The book starts with many of the topics of a standard introductory physics course, but with the topics selected and presented in a way to be of use in the second half, which develops the physics of electronic devices. In particular, these chapters cover the fundamentals of quantum mechanics, multi-electron systems, crystal structure, semiconductor devices, and logic circuits. The mathematical complexities are alleviated by intuitive physical arguments. Students are encouraged to use their own programming skills to solve problems. An instructor's manual is available from the authors. Als Ergebnis jahrelanger Bemühungen, eine Ausbildungslücke zu füllen, lehrt dieses Buch den Informatiker die Physik des Computers. Einer allgemeinen Einführung folgt die durchgängige Beschreibung der Physik elektronischer Bauteile. Die komplexe mathematische Darstellung wird durch intuitive physikalische Argumente verständlich gemacht.