Today modelling, simulating and optimizing are essential tools in engineering sciences and are increasingly applied in natural and social sciences. These fields of research are the centre of three collaborative research centres and various DFG research groups at Technische Universität Dortmund where scientists from engineering science, mathematics, computer science, statistics as well as economics and social sciences work together successfully. Technische Universität Dortmund regards this interdisciplinary cooperation as an essential element of its excellency in methodical science as well as in the fields of application. It has specifically strengthened this area by supporting the research association “Modelling and Simulation”, especially by the temporary establishment of junior groups. And it will continue to do so.