Overpotential charts the twists and turns in the ongoing quest to create the perfect fuel cell. By exploring the gap between the theory and practice of fuel cell power, Matthew N. Eisler opens a window into broader issues in the history of science, technology, and society after the Second World War, including the sociology of laboratory life, the relationship between academe, industry, and government in developing advanced technologies, the role of technology in environmental and pollution politics, and the rise of utopian discourse in science and engineering.