Traditional economic thinking identifies supply as the most important factor in long-run economic changes. In 1982 Neil McKendrick presented a forceful, revisionist perspective emphasizing the equally great importance of demand as a necessary feature of such change. This selection argues that McKendrick’s consumerist emphasis on demand-led growth is inadequate, and that any theoretical approach to economic history that focuses primarily on the interaction between supply and demand cannot explain economic trends. Supply and demand are themselves products of historical and social forces, and these forces must be the analytical starting point for any adequate theory of economic change.