The Workshop on Energy and Transportation took place on January 7-9, 2002, in Washington, DC. This workshop was the second in a series of workshops that comprise the study Challenges in the Chemical Sciences in the 21st Century. The purpose of this study was to carry out a survey of the current status of the chemical sciences, including chemistry and chemical engineering, and its interfaces with other disciplines such as mechanical engineering, physics, materials science, and the biological sciences. The goal of the study was to assess trends across these broad fields and identify key opportunities and challenges