Dave Callans was born in Joliet, Illinois in 1960. He is Professor of Medicine at the Perelman School of Medicine of the University of Pennsylvania. He has a busy practice of cardiac electrophysiology and participates in clinical research to push this field forward. He has authored over 300 peer reviewed manuscripts about various topics in clinical electrophysiology. He is devoted to carrying on the legacy of his mentor Mark E. Josephson, who emphasized the importance of a deep understanding of the physiology of electrophysiology. He has assumed authorship of the iconic text Josephson's Clinical Cardiac Electrophysiology to ensure that his mentor's voice continues to be heard