Eleven Seconds into the Unknown: A History of the Hyper-X Program is a sequel to the author’s first book on the X-43A/Hyper-X project, Road to Mach 10: Lessons Learned from the X-43A Flight Research Program. The Hyper-X program involved the efforts of numerous governmental and commercial organizations, each with its own culture, experience, and tradition. A central theme of the Hyper-X story is how these disparate groups and organizations became a unified team working toward a common goal. Making the team’s task more difficult was the technological, political, and funding challenges during nearly fifty years of scramjet development. Eleven Seconds into the Unknown: A History of the Hyper-X Program addresses these issues in compelling fashion, and will appeal to anyone interested in high-speed flight, aerospace history, the organization and management of technological projects, and the future of spaceflight.