Curtis Callan is the James S. McDonnell Distinguished University Professor of Physics at Princeton University. He received his B.A. from Haverford College in 1961 and his Ph.D. in physics from Princeton in 1964. He has held numerous posts and positions prior to his appointment at Princeton, including assistant professor at Harvard University, visiting professor at the University of Paris, Gordon Moore Scholar at the California Institute of Technology, and visiting professor at the Institute for Advanced Study, among others. His research interests include quantum field theory, string theory, dissipative quantum mechanics and the quantum fracture of materials. More recently, his interests have shifted toward theoretical problems in cellular biology where he is involved in the design and analysis of novel experiments designed to answer unconventional, theoretically motivated, questions in biology. He is the recipient of numerous awards and honors, including the Sakurai Prize for Theoretical Particle Physics from the American Physical Society in 2000, and the Dirac Medal from the Abdus Salam International Center for Theoretical Physics in 2004. In addition, he is an elected Fellow of the Alfred P. Sloan Foundation, the American Physical Society, American Academy of Arts and Sciences, and is a member of the National Academy of Sciences.