The topic of this book has fascinated me for a long time. I have given lectures on the economic theory of public enterprise as professor at the universities of Bonn, Vienna and Graz since 1974 and as visiting professor at the London School of Economics since 1976. I discussed particular problems at scientific conferences. This book is the result of all this scientific business. I have greatly benefited from discussing various ideas with my colleagues. In Germany and Austria, above all N.Andel, Ch.B.Blankart, D.Elixmann, B.Genser, G.Gyarfas, R. Holzmann , Ch.Seidl, J.Tillmann, R.Watzke, W.Wiegard and G.Winckler have to be mentioned. At London School of Economics, discussions with A.Atkinson, Ch.Foster, S.Glaister, A.R.Prest, D.Quarmby, W.H.Robson, A.Sen, R.Turvey and A.A. Walters have been indicative for me. Last not least my thanks go to my German, Austrian and British students, especially to the critical ones among them. Needless to say that mentioning these discussion partners only means thanking them. The responsibility for any remaining faults is only at me.