This Festschrift volume, published in honor of Christoph Walther, contains contributions written by some of his colleagues, former students, and friends. In celebration of the 60th birthdays of Alejandro P. Buchmann, Sorin A. Huss and Christoph Walther, a colloquium was held on November 19th, 2010 in Darmstadt, Germany. The articles collected herein cover some of the main topics of Christoph Walther's research interests, such as formal modeling, theorem proving, induction, and termination analysis. Together they give a good overall perspective on the formal verification of the correctness of software systems.