Since the publication of Markowitz's article on “Portfolio Selection,” which was subsequently expanded into a monograph, there has been a great deal of further articulation, a not inconsiderable amount of mathematical programming and sensitivity analysis, the arrival of several competing portfolio balance models, and a near revolution in the theory of money and asset preference. While few formulas for solving a practical problem can claim to have generated as much theoretical fall-out, the new approach to portfolio management apparently has not been very successful at reaching the practitioners for which it was intended.