Originally published in 1957, this short essay on an intricate historical theme, to which, according to the author, it is customary and proper to devote large volumes, was designed to whet but not to satisfy the appetite. The chapters provide the framework for a presentation of the views of theorists from Plato to Lenin on the character and purpose of political association. Its perusal will, the author hoped, provoke a wider and more intense study of social and political thought; it was not intended to be regarded or used as a substitute for further reading and reflection but as an invitation to prosecute these activities.