[This book] ... is a comprehensive treatise on economic science that would lay the foundation for a massive shift in intellectual opinion that is still working itself out fifty years after publication. Not even such milestones in the history of economic thought as Adam Smith's Wealth of Nations, Alfred Marshall's Principles, Karl Marx's Capital, or John Maynard Keynes's General Theory can be said to have such enduring significance and embody such persuasive power that today's student and scholars, as much as those who read it when it first appeared, are so fully drawn into the author's way of thinking. For this reason ... this Scholar's Edition is the original 1949 magnum opus that represents such a critical turning point in the history of ideas, reproduced (with a 1954 index produced by Vernelia Crawford) for the fiftieth anniversary of its initial appearance ...