Marcel Hertogh is professor “Infrastructure Design and Management” at Delft University of Technology. He set up, restructured and assessed numerous large projects, such as high speed lines, waterways, highways, and large tunnel projects, as well as city renewal. He was responsible for two research projects for the European Commission in this field. He initiated the network Netlipse for knowledge exchange on large infrastructure projects, and was program director. His (joint) PhD was about Playing with Complexity.