First published in 1996. The relationship between the present discounted value of future cash flows and discounted excess earnings should be viewed as a mathematical property of a double-entry book[1]keeping system based on clean surplus. The purpose of this anthology is to facilitate future research by highlighting these historical developments and by showing how more recent theoretical and empirical research fits into the earlier history. The book is divided into four sections: historical overview; analytical properties of clean surplus; the theory of the clean surplus equation; and empirical implications.