From the early 1950's until his untimely death in Ayacucho, Peru, in August of 1970, Dr. Eric 0. Callen was recognized as the world's leading authority in the area of prehistoric human coprolite analysis. During his nearly 20 years of coprolitic research Dr. Callen completed and published the analyses of samples recovered from archeological sites in many areas of the world including coprolites from Huaca Prieta de Chicama in Peru (Callen and Cameron, 1955, 1960); from Tamaulipas, Mexico (Callen, 1963, 1965, 1967a); from Tehuacan, Mexico (Callen, 1967b); from Lazaret, France (Callen, 1969); and from the Glen Canyon in Utah (Callen and Martin, 1969). In addition to these studies Dr. Callen examined but had not yet published the analyses of prehistoric human coprolites recovered from archeological sites in Florida, Kentucky, Egypt and Peru. Dr. Callen was one of the pioneers in the field of coprolitic analysis, and his research set the standards for others to follow. His colleagues therefore felt that it was essential that his many notes, records and reference materials not become lost, scattered, or accidently discarded. Those of us who had seen and used his collections knew of its important value and of the contributions it could continue to make in the field of human coprolite analysis. Fortunately, his complete collection was saved and is now catalogued and available for use. The Eric 0. Callen Collection is stored and maintained by the Laboratory of Anthropology at Texas A&M University. The collection consists of 15,213 micro-