IJ:1 June of 1987 the Center for Applied Mathematics and Computer Science at San Jose State University received a bequest of over half a million dollars from the estate of Mrs. Marie Woodward. In the opening article of this collection of papers Jane Day, the founder of the Center, describes the background that led to this gift. In recognition of the bequest it was decided that a series of Woodward Conferences be established. The First Woodward Conference took place at San Jose State University on June 2-3 1988. The themes of the conference were the Theoretical, Computational and Practical Aspects of Wave Phenomena and these same themes have been used to divide the contributions to this volume. Part I is concerned with papers on theoretical aspects. This section includes papers on pseudo-differential operator techniques, inverse problems and the mathematical foundations of wave propagation in random media. Part II consists of papers that involve significant amounts of computation. Included are papers on the Fast Hartley Transform, computational algorithms for electromagnetic scattering problems, and nonlinear wave interaction problems in fluid mechanics. vi Part III contains papers with a genuine physics flavor. This final section illustrates the widespread importance of wave phenomena in physics. Among the phenomena considered are waves in the atmosphere, viscous fingering in liquid crystals, solitons and wave localization.

Structures in Nature are ubiquitous and fascinating. In natural and mathematical systems nonlinear structures, roughly speaking, are those resulting from nonlinear equations, the investigation of which forms a large and integral part of the new branch of science-the nonlinear science. Like nonlinear science in general, non linear structures is a truly interdisciplinary subject which involves physicists, chemists, biologists, material scientists, mathematicians, engineers, etc. In view of the recent rapid developments in this subject and the existence of a converging picture which acts to unify some of the previously considered separate subfields of research, we think it is time to bring together various experts to exchange ideas and share their newest findings. The Second Woodward Confer ence afforded us a chance to do exactly this. Accordingly, this second conference in the series was devoted to the subject of Nonlinear Structures in Physical Sys tems: Pattern Formation, Chaos and Waves, and was held at San Jose State Uni versity on November 17-18, 1989."