This IMA Volume in Mathematics and its Applications RADAR AND SONAR, PART II is based on the proceedings of the second week of the IMA summer program "Radar and Sonar". Week two was devoted to the presentation of problems and solutions of problems in Radar and Sonar. vVe are grat.eful to Alberto Griinbaum, Marvin Bernfeld and Richard Blahut for organizing the program. We also take this opportunity to thank those agencies whose financial support made the summer program possible: the Air Force Office of Scientific Research, the Army Research Office, the National Science Foundation, the National Security Agency and the Office of Naval Research. A vner Friedman Willard Miller, Jr. PREFACE This volume contains a representative discussion of mathematical problems that arise in radar and sonar and is based on the lectures that were given during the second week of the IMA summer program RADAR AND SONAR, June IS-June 29, 1990. (The first week was devoted to three sets of tutorial lectures and the lecture notes from that part of the program appear in an earlier IMA volume.) The second week was run as a workshop of contributed papers without formal review. The speakers were selected to cover a broad range of problems in this area.