This article was prepared by L. J. Perry, School of Economics, University of New South Wales. The author is especially grateful to Dr R. Horn, Professor J. Nevlle, Bill Rao and anonymous referees for their constructive criticisms. Other people who have helped in various ways are Ron Bewley, Judy Francis, Professor Kakwani, Kevin Forde, and Dr K. Rivett. None of these people necessarily agree with the contents and any errors are the responsibility of the author.