Using methods that take account of a number of different effects, an international team has tried to estimate the effects of various tariff-cutting formulas in the Tokyo Round. They find that substantial liberalization would produce large gains in global welfare with relatively little disturbance to employment and only moderate shifts in trade balances. The developing countries have much to gain, especially in manufactures even if textiles remain restricted. In a difficult field, this is an outstanding piece of work, with many incidental results of great interest.