Welcome to The American Journal of Physics (AJP) Online. AJP publishes papers that meet the needs and intellectual interests of college and university physics teachers and students. Articles provide a deeper understanding of physics topics taught at the undergraduate and graduate level, insight into current research in physics and related areas, suggestions for instructional laboratory equipment and demonstrations, insight into and proven suggestions for better teaching methodologies, insight into how college students learn physics, information on historical, philosophical and cultural aspects of physics, annotated lists of resources for different areas of physics, and book reviews.