Matthew Wright is Senior Lecturer in Acoustics at the Institute of Sound and Vibration Research (ISVR). His B.Eng. was in Engineering Acoustics and Vibration and his Ph.D. was in Volterra series characterization and identification of nonlinear bioacoustic systems, both from the University of Southampton. His research interests include flow control for drag and noise reduction, turbofan inlet design, aeroacoustic theory, and violin acoustics, windfarm noise and the neuroscience of hearing. He is a Fellow of the Institute of Acoustics, a Fellow of the Institute of Mathematics and its Applications, a Senior Member of the American Institute of Aeronautics and Astronautics, a Member of the… Acoustical Society of America, and book reviews editor of the Journal of Sound and Vibration. He is editor and co-author of Lecture Notes on the Mathematics of Acoustics. In 2002 he was awarded an Advanced Research Fellowship by the UK's Engineering and Physical Sciences Research Council to study periodic orbits in sound and vibration, one of the results of which is this book.