I was originally induced to think about barriers to entry by some re search done for Charles River Associates, Inc., Boston, on behalf of their client IBM Corporation, Armonk, N.Y. After the end of this re search project I continued to work on entry barriers and related is sues of market structure. The results of this effort are reported here. What I present is not a book in the traditional sense of the word. Due to other research and administrative obligations I could not, without substantial delay, present a more finished product. The rapid progress in the field of industrial organisation theory made me fear that my results could become obsolete if I further waited with their publica tion. I hope that the early presentation of a progress report rather than a much later publication of a finished product is not only in my interest but also in the interest of economics."

The following lecture notes were written shortly after I gave a course on capital theory in the winter-semester 1970/71 at the Univer sity of Heidelberg. While the general line of the argument is similar to the one in the course, I have modified and added a large number' of specific points in the process of writing the English version. I should like to emphasize the narrow limitations of the material covered in these notes. I have completely concentrated on steady states of stationary and exponentially growing economies, even up to the point where there is the danger of misleading the reader1 I have done this for several reasons. Other activities have not left me with a sufficient amount of time to be able to find the unifying principle of analysis and mode of presentation for the dynamic aspects of capi tal theory which would have made it worthwhile to add a sizeable book to the large body of literature in this field. On the other hand over the last couple of years I have become increasingly aware that some of the results in steady state capital theory (which could be derived without too much mathematical effort) are of relevance in present day dis cussions about the political role of economic theory and the relative merits of orthodox and radical economics. Also these results seemed not to be known by' mO$ of the participants in these discussions."

Die Analyse okonomischer Fragestellungen insbesondere wirtschaftspolitischer Probleme mit Hilfe eines geeigneten theoretischen Instrumentariums, die "angewandte Wirtschaftsforschung", wird in diesem Band behandelt. Ziel ist es dabei, die Vielseitigkeit der Forschungen Gottfried Bombachs in der Vielseitigkeit der Interessen seiner Schuler zu spiegeln. Die Leistungsfahigkeit der modernen Theorie wird dokumentiert, das Verstandnis okonomischer Zusammenhange und ihrer Anwendungen auf die Entwicklung wirtschaftspolitischer Strategien werden gefordert.