This is the comprehensive history of the nuclear rocket propulsion system that will enable robotic and human exploration of our solar system. During a two decade period, from the 1950s to the 1970s, the US government’s Rover and NERVA program developed the system and ultimately succeded in demonstrating the propulsion capabilities required for deep space exploration missions. This history and its amazingly robust reference sources are invaluable in identifying the significant technological developments that will have to be resurrected to perform the deep space missions now being planned. This is the only comprehensive source for detailed data required to implement the thermal nuclear propulsion system that has been developed and proven to the point that it could be relied upon for actual mission use. This book is on the NASA Administrator’s recommended reading list.