The Advanced Research Institute (A.R. 1.) on "the efficiency of Manufacturing Systems" was held under the auspices of the NATO Special Programm~ Panel on Systems Science as a part of the NATO Science Committee's continuous effort to promote the advancement of science through international co-operation. Advanced Research Institutes are organised for the purpose of bringing together experts in a particular field of interest to identify and make known the present state of knowledge in that area and, through informed debate, to make recommendations for directions for future research that would benefit the community at large. To this end two kinds of contribution were obtained by invitation. There were those papers which were about the current state of work in the area of manufacturing systems and its organisation; in addition three theme papers were presented to provide a stimulus to the discussion in terms of ways of thinking, both about the area and about the kind of research needed.