Mounting pressure in the early 1960s from the National Academy of Sciences (NAS) led to NASA's conclusion that flying scientifically trained crewmembers would generate greater returns from each mission. In selecting the first group of scientist-astronauts, NASA had one firm requirement; any person accepted into the programme would have to qualify as a military jet pilot. This book provides unique access to the story of how scientists were accepted into the American Space Programme, and reveals how, after four difficult decades, the role of the heroic test pilot astronaut has been replaced by men and women who are science orientated space explorers.