Mechanical engineering, an engineering discipline borne of the needs of the industrial revolution, is once again asked to do its substantial share in the call for industrial renewal. The general call is urgent as we face profound is sues of productivity and competitiveness that require engineering solutions, among others. The Mechanical Engineering Series features graduate texts and research monographs intended to address the need for information in contemporary areas of mechanical engineering. The series is conceived as a comprehensive one that covers a broad range of concentrations important to mechanical engineering graduate education and research. We are fortunate to have a distinguished roster of consult ing editors on the advisory board, each an expert in one of the areas of concentration. The names of the consulting editors are listed on the next page of this volume. The areas of concentration are applied mechanics, biomechanics, computational mechanics, dynamic systems and control, en ergetics, mechanics of materials, processing, thermal science, and tribology. Fred Leckie, our consulting editor for applied mechanics and I are pleased to present this volume in the Series: Principles of Analytical System Dy namics, by Richard A. Layton. The selection of this volume underscores again the interest of the Mechanical Engineering Series to provide our read ers with topical monographs as well as graduate texts in a wide variety of fields.