The systematic development of software systems is a central task of computing science. A software system is the result of putting together knowledge about the application, the requirements and the structures of computing science. Under the heading CIP (Computer-aided Intuition-guided Programming), a group of researchers led by Prof. F.L. Bauer and Prof. K. Samelson started work in 1975 in the direction of formal program specification, transformational programming, and tool supportfor program development. The collection of papers in this volume presents examples of a formal approach to programming language concepts and program development based on algebraic specifications and program transformations. Examples are also presented of evolutions and modificationsof the original ideas of the CIP project. The topics range from descriptionsof the program development process to derivations of algorithms from specifications. The volume is dedicated to Prof. F.L. Bauer.