Helmut Wiedemann is Professor Emeritus of Applied Physics and of the Stanford Synchrotron Radiation Laboratory. He obtained his PhD from the University of Hamburg in 1971 and worked at DESY before becoming the assistant director of the 18 GeV PEP Storage Ring at SLAC in 1975. In 1980 he became adjunct professor and a full professor of applied physics (photon science) in 1983. His research interests include developments in theoretical and experimental accelerator physics, particle sources, linear accelerators, storage rings and synchrotron radiation sources, with special interests in developing high brightness light sources at short pulse duration. Professor Wiedemann is a Fellow of the American Physical Society.