Claude A. Piantadosi presents a rich history of American space exploration and its extraordinary achievements. He emphasizes the importance of continuing manned and unmanned space missions to American and human interests, and he stresses the many adventures that still await us in the unfolding universe. Remaining cognizant of space exploration¿s practical and financial obstacles, Piantadosi nevertheless challenges us to revitalize our leadership in space and reap its vast scientific bounty. Along with being a captivating story of ambition, invention, and discovery, Piantadosi¿s history explains why space exploration is increasingly difficult and why space experts always seem to disagree. He argues that the future of the space program requires merging the practicalities of exploration with the constraints of human biology. Space science deals with the unknown, and the margin (and budget) for error is small. Lethal near-vacuum conditions, deadly cosmic radiation, microgravity, vast distances, and highly scattered resources remain immense physical problems.