This paper provides a historical perspective for the discussion on ecological economics as a special field of research. By studying the historical background of ecological economics, the present discussions and tensions inside the field might become easier to understand and to relate to. The study is inspired by other studies of the emergence of new research areas done by sociologists and historians of science, and includes both cognitive and social aspects, macro trends and the role of individuals. The basis for the paper is a combination of literature studies and interviews with key researchers from the field. The story opens with the emergence of the new environmental agenda in the 1960s, which was influenced by the scientific development in biology and ecology. Then it is outlined how the environmental challenge was met by economics in the 1960s. Around 1970 the basic ideas of ecological economics were given modern formulations, but it took a long gestation period from the beginning of the 1970s to the end of the 1980s, before ecological economics took shape. This preliminary version of the paper does not include the formation of the personal relationships between the actors and the meetings that were decisive for the formal establishment of ecological economics.