This a position paper outlining the way thinking about co-operative buildings has developed over the last 30 years. It does not attempt to review the field in an objective manner but summarises the particular viewpoint of the author by reviewing selected co-operative projects. Starting briefly with the author’s final year thesis, the paper touches on projects for Cedric Price and Walter Segal with contrasting ideas about co-operation. The paper then expands on the concept of co-evolutionary theory including the co-operative evolution of buildings with each other, with the environment and with the inhabitants. It concentrates on the most recent co-evolutionary projects for buildings and cities. It describes the Groningen experiment which demonstrates these principles with a model which allows the co-operative development of the city with the “collective social ambition of the inhabitants.” The paper ends with a note about the “Talking Cities” project for global co-operation in the evolution of urban form. These examples are presented as a series of “vignettes” or glimpsas at history.