"To understand the power elite we must attend to three major keys: I.. . . .the psychology of the several elites in their respective milieux. In so far as the power elite is composed of men of similar origin and education, in so far as their careers and their styles of life are similar, there are psychological and social bases for their unity, resting upon the fact that they are of similar social type and leading to the fact of their easy intermingling. . .
II. Behind such psychological and social unity as we may find, are the structure and mechanics of those institutional hierarchies over which the political directorate, the corporate rich, and the high military now preside. The greater the scale of these bureaucratic domains, the greater the scope of their respective elite's power. . .
III. The unity of the power elite, however, does not rest solely on psychological similarity and social intermingling, nor entirely on the structural coincidences of commanding positions and interests. At times it is the unity of a more explicit co-ordination" (The Power Elite, 1956, p. 19).