Astrophysicist and space pioneer James Van Allen (1914-2006), for whom the Van Allen radiation belts were named, was among the principal scientific investigators for twenty-four space missions, including Explorer I in 1958, the first successful U.S. satellite; Mariner 2's 1962 flyby of Venus, the first successful mission to another planet; and the 1970s Pioneer 10 and Pioneer 11 missions that surveyed Jupiter and Saturn. Although he retired as a University of Iowa professor of physics and astronomy in 1985, he remained an active researcher, using his campus office to monitor data from Pioneer 10 - on course to reach the edge of the solar system when its signal was lost in 2003 - until a short time before his death at the age of ninety-one. Now Abigail Foerstner blends space science drama, military agendas, cold war politics, and the events of Van Allen's lengthy career to create the first biography of this highly influential physicist. Drawing on Van Allen's correspondence and publications, years of interviews with him as well as with more than a hundred other people, and declassified documents from such archives as the Jet Propulsion Laboratory, the Kennedy Space Center, and the Applied Physics Laboratory, Foerstner describes Van Allen's life from his Iowa childhood to his first experiments at White Sands to the years of Explorer I until his death in 2006. Often called the father of space science, James Van Allen led the way to mapping a new solar system based on the solar wind, massive solar storms, and cosmic rays. Pioneer 10 alone sent him more than thirty years of readings that helped push our recognition of the boundary of the solar system billions of miles past Pluto. Abigail Foerstner's compelling biography charts the eventful life and time of this trailblazing physicist.