<P>Of the nine articles reprinted in this volume originally published in 1984, those by <I>Ladelle, Hotelling</I> and <I>Anton </I>are recognized as being the classic articles on the depreciation of a single ¿machine¿. Each of these articles was published in a journal that is often not accessible and reprinted here has brought them together in one place. For many years accountants have dealt with depreciation and capital maintenance as a static problem. This volume recognizes its dynamic aspects. </P>