During the 1960s Caldwell was virtually a lone voice in attempting to establish policies for the environment because such a holistic and interdisciplinary approach to solving environmental problems did not then exist. In 1962 his groundbreaking article “Environment: A New Focus for Public Policy?” appeared in "Public Administration Review," launching development of a new subfield of "environmental policy studies". After 1962, he changed the main focus of his career towards examining policies for protecting the quality of the human environment. In 1972 he was the catalyst for founding the School of Public and Environmental Affairs (SPEA) at Indiana University, Bloomington. His 1976 article "Novus Ordo Seclorum: The Heritage of American Public Administration" in "Public Administration Review" was a defining paper in the modern history of public administration.