On March 1 and 2, 1990, Sandia National Laboratories, Albuquerque, N. Mex., organized a meeting of Earth scientists in Denver, Colo. This meeting set out to develop a research program that would embrace common goals of the Continental Scientific Drilling Program (CSDP) and the Yucca Mountain Project (YMP). The motivation for this meeting came from many directions, including Congress, which identified the solution of waste-isolation problems as a potential contribution of the CSDP. Another impetus is that Yucca Mountain itself lies in a region of dramatic crustal extension and melting, which are crustal processes of great scientific interest to the CSDP program.