In this paper we give a short overview of the research conducted, initiated, and supervised by Klaus Neumann from the early sixties up to present. Of course, we do not claim exhaustiveness of our review. The major themes of research can be clustered into the three main areas sketched in Sections 2 to 4:
Control Theory and Dynamic Programming (1960s and 1970s)
GERT Networks (1970s to 1990s)
Resource-Constrained Project Scheduling (since 1990s)
In any of those fields, Klaus Neumann has significantly influenced the development of OR in Germany and beyond. From the very beginning, his research has combined solid mathematical foundation and applicability of theoretical results. The relevance of his achievements to the treatment of real-world problems has been reflected in many applied research and development projects. A selection of the projects that have been carried out in cooperation with different industrial partners is sketched in Section 5.