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.

• H. Dieter Zeh and the History of the Foundations of Quantum Mechanics.- Emergence of the Classical World from within our Quantum Universe.- Decoherence: From Interpretation to Experiment.- Experimental decoherence in molecule interferometry.- When Zeh meets Feynman: how to avoid the appearance of a classical world in gravity experiments.- Preferred basis, decoherence and the quantum state of the Universe.- Wave Function First - H.D. Zeh and the Foundations of Physics.- Geometrodynamics as Functionalism about Time.- Quantum Hierarchical Systems: Fluctuation Force by Coarse-Graining, Decoherence by Correlation Noise.- Decoherence and the puzzle of quantum Brownian motion in a gas.- On the statistical viewpoint concerning the second law of thermodynamics — a reminder on the Ehrenfests’ urn model.- Explanation, the Progress of Physical Theories and Computer Simulations.- Searching for Dieter Zeh.