Robert Adams celebrated his 70th birthday on July 23, 1996. Forty years ago American Antiquity published his first journal article, which helped launch a remarkable career. Adams has influenced not only fundamental aspects of social evolutionary theory and archaeological reconnaissance surveys but also the structure of support for science in the United States and abroad. At the 1996 meetings of the Society for American Archaeology, Adams was awarded the Distinguished Service Medal. This essay traces the intellectual influences on Adams, the progress of his fieldwork, and the exposition and development of his ideas in his monographs and major essays. The significance of his work is assessed, and a bibliography of his principal archaeological writings is included.