This Research Experiences for Undergraduates award continues support for a highly successful mathematical activity at the University of Washington. Ten students will receive support in each of the next three years. They will work with two experienced faculty advisors on a broad range of questions generally classified as inverse problems. The problems involve both discrete and continuous environments with a decided slant toward physical applications. In gaining insight to the problems, computer experimentation will play a major role. Students will investigate problems associated with the computation of values of conductors in a network, on discrete versions of inverse problems in magneto-telluric theory and in gravitational theory. The fundamental issue is that of determining the conductivity throughout the interior of a conducting body from measurements of potential and currents on the surface. Similar questions arise in attempts to determine the shape of a gravitational mass from measurements of gravitational potential on the surface. Students will work in small teams and will submit papers on their research at the end of the program. The record of former students at this site is one of significant success. A number are pursuing graduate science degrees at outstanding U.S. institutions. It is expected that this trend will continue.