Philip M. Sadler has taught Harvard’s courses for new science teachers and for the next generation of professors, doctoral students in science. As F.W. Wright Senior Lecturer in Astronomy, he carries on Harvard’s oldest undergraduate course in science, Celestial Navigation. He directs one of the largest research groups in science education in the U.S., based at the Harvard-Smithsonian Center for Astrophysics. In 1999, Dr. Sadler won the Journal of Research in Science Teaching Award for work on assessing student understanding in science deemed “the most significant contribution to science education research” in the preceding year. His research interests include assessment of students' scientific misconceptions and how they change as a result of instruction, the development of computer technologies that allow youngsters to engage in research, and models for enhancement of the skills of experienced teachers. He was the executive producer of A Private Universe, an award-winning film on student conceptions in science. He won the Astronomical Society of the Pacific’s Brennan Prize for contributions to astronomy teaching in 2002. He is the inventor of the Starlab Portable Planetarium and many other devices used for the teaching of astronomy, worldwide. Materials and curricula developed by Dr. Sadler are used by an estimated twelve million students every year. Dr. Sadler earned a B.S. in Physics from MIT in 1973 and taught middle school science and mathematics for several years before earning a doctorate in education in 1992.