The paper analyses the old and new challenges to the theory and policy
of Free Trade. The old challenges have sought to undermine the case f
or Free Trade by citing one or another type of market imperfection. Th
us, the postwar period has seen two such challenges: factor market imp
erfections were analysed in the 1950s to 1970s, product market imperfe
ctions in the 1980s. The new challenges are twofold. One comes from th
e demands for Fair Trade as a precondition for Free Trade; the other,
from the concern that Free Trade, while efficient, immiserises the uns
killed in the richer countries.