Economics is everybody's business, like politics, and in this readably clear and quick exposition of economic theory from Plato through Keynes the author opens the door of a too-often closed corporation to the general public. The theories involving man's livelihood were a part of the times in which they were evolved:-the classic concepts based on aristocracy and feudalism gave way to mercantilism for the benefit of nations during the Renaissance; the eighteenth century, bringing the age of reason and enlightenment produced the physiocrats with their return to nature. Classicism and laissez faire of Smith, Malthus and Ricardo gave way to the French Utopians, Utilitarianism and socialism. Keynes, the Institutionalists represented by Veblen and others, and the researcher Mitchell who determined to build his theories on more than established facts, followed. Without critical rancour, the author gives the background and contributions of the major economic thinkers, in a way that reveals the shifts and growth of thought with the changing times.