Freedom of international trade has been favored by most economists since Adam Smith made a powerful case for it 220 years ago. Since then, free trade doctrine has come under sustained intellectual assault by politicians, businessmen, labor leaders, and even some economists. But the coherent arguments for trade restrictions all contain one or more of three attributes: their conclusions are not robust when small alterations are made in their assumptions, thus they require unrealistically precise information for effective application; they are less efficient than other policies for achieving the same goals; and their gains come at the expense of other countries, inviting emulation or retaliation that generally negates the supposed benefit. The latter danger points logically to a pact of mutual restraint among countries, such as the General Agreement on Tariffs and Trade (managed by the new World Trade Organization), which recognizes that trade is an expansible sum from which all can gain. Douglas Irwin provides a superb examination, in readable but closely reasoned form, of the intellectual history and the analytical content of the various assaults on free trade over the years. The bibliography alone is worth the price.