Software verification is the study of formally proving the correctness of a program with respect to a given specification. Even after 40 years of research and considerable success stories in industrial applications software verification remains an ongoing research topic. The state of the art is that given a sufficiently rich specification an object-oriented program can be in most cases automatically verified using verification systems like the KeY-System. The KeY-System is a software verification and testing system for Java that is developed by the research groups of Prof. Dr. Bernhard Beckert (Univ. of Koblenz-Landau, Germany), Prof. Dr. Reiner Hhnle (Chalmers Univ. of Tech., Sweden), and Prof. Dr. Schmitt (University of Karlsruhe, Germany). This book describes the theory and the implementation of the KeY-System and the development of a prototypical version of the KeY-System for the verification of C programs. In particular the C dialects ANSI C, MISRA C, and C0 are regarded.