Elmar Stahl is a full professor at the University of Education, in Freiburg, Germany. He is the head of the Institute of Media in Education since 2007. He received a diploma in Psychology with a thesis about binocular rivalry (visual perception) in 1995. In 2001 he received his Ph.D. with a thesis about knowledge acquisition and learning processes by writing hypertexts. In 2006 he received his habilitation (= a kind of second PhD Thesis, common in Germany to qualify for a tenure position as a full professor). His current research interests include research and teaching on video-based learning, epistemological beliefs, learning by hypermedia construction and help seeking within interactive learning environments. He is (together with Prof. Dr. Rainer Bromme, University of Muenster, Germany) the founder and head of the European network of Research on Epistemological Beliefs, sponsored by the DFG (German Research Foundation). His research work has been published in Review of Educational Research, Learning and Instruction, Computers & Education, Computers in Human Behavior and some other educational journals.