THIS book is not a revision but a development of the ideas contained in my thesis "Postulates of Welfare Economics" submitted to the University of London for the Ph.D. degree in 1943. I would like to express my deep gratitude to J. R. Hicks. Apart from the heavy debt I owe to his writings, I had the advantage of his constant advice and criticism in writing this book during my tenure of the Drummond Fraser Research Fellowship at Manchester University.
I would also like to thank Prof. Hayek who supervised my thesis and from whose mellow scholarship in the history of economic thought I have benefited, and Prof. Robbins for reading the manuscript and giving me kindly encouragement. None of my teachers is of course responsible for the errors that may remain in the book.
My thanks are due to the editors of the Economica for permission to use my article "The Classical View of the Economic Problem".