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 issues 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 con temporary 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 consulting editors on the advisory board, each an expert in one of the areas of concen tration. The names of the consulting editors are listed on the next page of this volume. The areas of concentration are: applied mechanics; bio mechanics; computational mechanics; dynamic systems and control; energetics; mechanics of materials; processing; thermal science; and tribology. Professor Marshek, the consulting editor for dynamic systems and control, and I are pleased to present the second edition of Vibration of Discrete and Continuous Systems by Professor Shabana. We note that this is the second of two volumes. The first deals with the theory of vibration.