"'Atomic Power in Space,' a history of the Space Isotope Power Program of the United States, covers the period from the program's inception in the mid-1950s through 1982. Written in non-technical language, the history is addressed to both the general public and those more specialized in nuclear and space technologies. The Space Isotope Power Program has been highly successful and has made major contributions to the overall space program of the United States. It has been part of notable technical triumphs and large-scale organizational endeavors of the space and nuclear age and offers lessons from the program perspective on the problems of modern-day research and development. It is important to document the history now, while key participants can be located to relate their first-hand experiences. The story is told at a number of levels: developments and achievements at the technical level; major events in the key institutions closely involved in RTG technology, and the larger milieu of the time. A chronology (see Appendix) presents important events in these different lines of action for the period covered by the history. A Bibliography indicates major sources used in developing the different lines contributing to the total story; of course, classified documents were not used."