Interest in economics and politics, indeed, in the trend and problems of social development in general, cannot be enlightened without an understanding – regardless of the conclusions drawn from it – of the ideas of Karl Marx. Ignorance of Marxism, or even indifference to it, is as inexcusable in the fields of social science and politics as ignorance of Newton and Darwin would be (to use a loose but adequate comparison) in the fields of physics and biology. The belief that Marxism has been outlived, or that it is irrelevant to events and problems of our day, or that it has failed in this or that or in all respects, is nowhere so widely held as in the United States. It would be more appropriate to hold that this belief itself, and in all its forms, has been outlived and is irrelevant to the need to know Marx’s ideas.