One of the first books in the classic Addison Wesley OD series in the late 1960s was a version of Lawrence and Lorsch’s (1969) seminal work on organizations as open systems. Early formulations of OD are virtually all based on positivist open systems premises, which continue to be prominent in OD treatises and textbooks. When viewing organizations as if they are like living systems, it makes sense to build models of optimal organizing in a given environment and compare a given team or organization to them. It also makes sense to assess them against standards for “healthy” organizations and to prescribe interventions or treatments based on an “objective” diagnosis.