: This document contains a range of needs and requirements concerning the construction of a light control system for a floor of a university building. A description of the building architecture and of some pre-installed (light-)hardware is included. This problem description was the common input for all participants of the requirements engineering case study "Light Control". Key Words: requirements engineering, building automation, problem description Introductory Note This document gives an informal description of the problem "Light Control System", that is the subject of the considered case study. It is based on two previous versions that have been used in the Sonderforschungsbereich 501 "Development of Large Systems with Generic Methods", a large project at the Computer Science Department of the University of Kaiserslautern. The initial version was created in 1995 by Stefan Queins and Gerhard Zimmermann. The second version (reported in [Fe+99]) integrate...