Gemini was one of the early pioneering efforts in the developing space capability of this nation. The initiation of this program was timed to take advantage of the knowledge gained in our first series of manned space flights - Project Mercury. The Mercury program successfully demonstrated manned orbital flight. Perhaps more important it provided extensive information on how to build and fly spacecraft for the more complex missions yet to come. Drawing on this experience, the Gemini program was able to produce for its time a highly flexible space vehicle of considerable operational capability. These characteristics enabled a rapid expansion of American flight horizons.

https://history.nasa.gov/SP-4002/contents.htm Includes index.