This book is a long-delayed product of a series of lectures that I gave in June, 1956 at a conference at Wabash College directed by John Van Sickle and Benjamin Rogge and sponsored by the Volker Foundation. In subsequent years, I have given similar lectures at Volker conferences directed by Arthur Kemp, at Claremont College, directed by Clarence Philbrook, at the University of North Carolina, and directed by Richard Leftwich, at Oklahoma State University. In each case I covered the contents of the first two chapters of this book, dealing with principles, and then applied the principles to a varied set of special problems.

I am indebted to the directors of these conferences not only for inviting me to give the lectures, but even more for their criticisms and comments on them and for friendly pressure to write them up in tentative form, and to Richard Cornuelle, Kenneth Templeton, and Ivan Bierly of the Volker Foundation who were responsible for arranging the conferences. I am indebted also to the participants who, by their incisive probing and deep interest in the issues, and unquenchable intellectual enthusiasm, forced me to rethink many points and to correct many errors. This series of conferences stands out as among the most stimulating intellectual experiences of my life. Needless to say, there is probably not one of the directors of the conferences or participants in them who agrees with everything in this book. But I trust they will not be unwilling to assume some of the responsibility for it.

I owe the philosophy expressed in this book and much of its detail to many teachers, colleagues, and friends, above all to a distinguished group I have been privileged to be associated with at the University of Chicago: Frank H. Knight, Henry C. Simons, Lloyd W. Mints, Aaron Director, Friedrich A. Hayek, George J. Stigler. I ask their pardon for my failure to acknowledge specifically the many ideas of theirs which they will find expressed in this book. I have learned so much from them and what I have learned has become so much a part of my own thought that I would not know how to select points to footnote.

I dare not try to list the many others to whom I am indebted, lest I do some an injustice by inadvertently omitting their names. But I cannot refrain from mentioning my children, Janet and David, whose willingness to accept nothing on faith has forced me to express technical matters in simple language and thereby improved both my understanding of the points and, hopefully, my exposition. I hasten to add that they too accept only responsibility, not identity of views.

I have drawn freely from material already published. Chapter i is a revision of material published earlier under the title used for this book in Felix Morley (ed.), Essays in Individuality (University of Pennsylvania Press, 1958) and in still a different form under the same title in The New Individualist Review, Vol. I, No. 1 (April, 1961). Chapter vi is a revision of an article by the same title first published in Robert A. Solo (ed.), Economics and the Public Interest (Rutgers University Press, 1955). Bits and pieces of other chapters have been taken from various of my articles and books.

The refrain, "But for my wife, this book would not have been written," has become a commonplace in academic prefaces. In this case, it happens to be the literal truth. She pieced together the scraps of the various lectures, coalesced different versions, translated lectures into something more closely approaching written English, and has throughout been the driving force in getting the book finished. The acknowledgment on the title page is an understatement.

My secretary, Muriel A. Porter, has been an efficient and dependable resource in time of need, and I am very much in her debt. She typed most of the manuscript as well as many earlier drafts of part of it.