The Evolution of Open Systems Theory is a revised and updated version of the paper that was published in 2000.  As well as accurately documenting the main advances in OST, including that component of it which has traditionally gone by the name of sociotechnical systems, deriving in part from Lewin’s work on systemic structures, it shows it was a completely separate stream of work from that derived from the other side of Lewin’s work, that which was fully within the closed systems Human Relations school. These streams did not come together in any major way until Weisbord unsuccessfully tried to integrate them in the 1980s.