David Hammer is an associate professor at the University of Maryland, College Park, with tenure in Physics and a joint appointment in Curriculum & Instruction. His research in physics education has focused on student “epistemologies”—how students understand knowing and learning—and on how instructors interpret and respond to student thinking. He conducts this work at levels from elementary school through university, currently in two projects funded by the National Science Foundation, Case Studies of Elementary Student Inquiry in Physical Science (Hammer and van Zee, ESI-9986846) and Learning to Learn Science: Physics for Bioscience Majors (Redish and Hammer, REC-0087519). In previous work he documented and studied learning in his own high school physics teaching, funded by a National Academy of Science Spencer Fellowship, and he collaborated with high school physics teachers in a project funded by the MacArthur / Spencer Professional Development Research and Documentation Program. Dr. Hammer served on the Physics Panel for the NRC Committee on Programs for Advanced Study of Math & Science in American High Schools, and he currently serves on editorial boards for several journals in science education and on advisory boards for several projects in science education.