The extension of human activity into outer space has been accompanied by a high degree of self-awareness of its historical significance. Few large-scale activities have been as extensively chronicled so closely to the time they actually occurred. Many of those who were directly involved were quite conscious that they were making history, and they kept full records of their activities. Because most of the activity in outer space was carried out under government sponsorship, it was accompanied by the documentary record required of public institutions, and there has been a spate of official and privately written histories of most major aspects of space achievement to date. When top leaders considered what course of action to pursue in space, their deliberations and decisions often were carefully put on the record. There is, accordingly, no lack of material for those who aspire to understand the origins and evolution of U.S. space policies and programs. The documents selected for inclusion in this volume are presented in two chapters: one covering the Mercury and Gemini projects and another chapter covering Project Apollo. Each section in the present volume is introduced by an overview essay. In the main, these essays are intended to introduce and complement the documents in the section and to place them in a chronological and substantive context. Each essay contains references to the documents in the section it introduces, and also contains references to documents in other volumes in this series. NASA-SP-2008-4407. NASA History Series. This is an 800+ page volume.