Huub Rottgering's main research interest is in observational studies of active galaxies, clusters and large scale structures in the distant universe with the aim of understanding their origin and evolution. An important focus is the usage of distant radio galaxies to study the properties of these objects. He has conducted large radio surveys with the Westerbork, VLA and GMRT radio telescopes to define good samples of radio sources. The radio galaxies from these samples have been studied over virtually the whole electromagnetic spectrum using both ground and space based telescopes to characterise their gas, dust and stellar contents. Recently, studies have been conducted using the ESO-VLT optical telescopes in Chile to study proto-clusters associated with powerful radio galaxies. Other scientific topics of interest include the nature of extremely red galaxies, starburst galaxies, cluster radio halos and tori of nearby active galactic nuclei. Rottgering has a considerable interest indeveloping interferometric techniques. As PI of the project the Development and Commissioning of LOFAR for astronomy (DCLA) and as first chair of LOFAR's Astronomy Research Committee (ARC), Rottgering has been playing a leading role in the development of LOFAR. He is also involved in the development of ground and space based optical and infrared interferometers (MIDI on the VLT interferometer, and ESA's Darwin and NASA's TPF space interferometers).