Claus Kiefer is a professor of theoretical physics at the University of Cologne. He does research on quantum gravity and the foundations of quantum theory as well as studying black holes and more general cosmological questions. In 2009, his essay, "Does Time Exist in Quantum Gravity?", was awarded second prize by the Foundational Questions Institute, New York. In 2012, his essay, "Can Effects of Quantum Gravity Be Observed in the Cosmic Microwave Background?" (written together with Manuel Krämer), was awarded first prize by the Gravity Research Foundation, Wellesley Hills, USA.