At the Geneva Superpower Summit in November 1985, Secretary of the former Soviet Union Mikhail Gorbachev and US President Ronald Regan agreed to pursue an international effort to develop fusion energy for peaceful purposes. At a time when tension between these cold war nations was very high, how were these leaders able to come together to work towards making nuclear fusion a feasible energy source? The Quest for a Fusion Energy Reactor is the story of the INTOR Workshop (INternational TOkamak Reactor) which brought together scientists and engineers from Europe, Japan, the United States, and the (then) USSR from 1978 to 1988 to share their individual research and work cooperatively on the design and development possibilities for harnessing nuclear energy. Drawing on his insights while serving as Vice Chairman of the INTOR Workshop, Weston Stacey offers an insider's account of both the participants' technical work and their fascinating political interactions under the blanket of the cold war. An accessible presentation of their research on the viability of designing, constructing, and operating a Tokamak experimental power reactor is combined with personal anecdotes of the obstacles Workshop leaders and participants faced as they strove to make progress on the global future of nuclear fusion technology while balancing their own countries' priorities. The Workshop led to the International Thermonuclear Experimental Reactor (ITER), construction of which began in 2009 with the goal of demonstrating the scientific and technical feasibility of fusion power.