This paper reports on recent research in the Federal Government on social cohesion. Social cohesion is defined as the willingness of members of a society to cooperate with each other in order to survive and prosper. Willingness to cooperate means they freely choose to form partnerships and have a reasonable chance of realizing goals, because others are willing to cooperate and share the fruits of their endeavours equitably. Social cohesion contributes to a wide variety of social outcomes such as health and economic prosperity. Part I of the paper relates how Federal Government researchers came to be interested in social cohesion. Part II discusses the concept of social cohesion. Part III presents a model of society to demonstrate how social cohesion works. Part IV concludes by discussing the policy significance of the model.