ITER presents the United States and its international partners with the opportunity to explore new and exciting frontiers of plasma science while bringing the promise of fusion energy closer to reality. The ITER project has garnered the commitment and will draw on the scientific potential of seven international partners, China, the European Union, India, Japan, the Republic of Korea, Russia, and the United States, countries that represent more than half of the world's population. The success of ITER will depend on each partner's ability to fully engage itself in the scientific and technological challenges posed by advancing our understanding of fusion. In this book, the National Research Council assesses the current U.S. Department of Energy (DOE) plan for U.S. fusion community participation in ITER, evaluates the plan's elements, and recommends appropriate goals, procedures, and metrics for consideration in the future development of the plan.