Since 1985, Los Alamos National Laboratory's (LANL) Institute of Geophysics and Planetary Physics (IGPP) has hosted a mantle convection workshop. Each year, senior scientists and graduate students meet for 2 weeks of formal and informal presentations and hands-on working groups. The workshop format has been to define focus topics and activities which are discussed in small subgroups. Focus group reports are then made to summarize previous work and define avenues of future research on specific topics. From July 8 to 19, 1991, the primary focus of discussion was mantle plumes. Mantle discontinuities and the effect of tectonic plates upon mantle convection were focus topics in previous workshops. Additional focus topics for this workshop included the differences between 2D and 3D convection and a discussion of benchmark problems for the European convection workshop, held in August 1991 in Weilburg, Germany. In addition to presentations, focus group reports, and the exchange of ideas by geodynamics researchers, a number of guest speakers from related fields helped provide background on relevant model constraints, motivate discussion, and promote communication between fields.