Volume 24 of Reviews in Mineralogy attempted to bring together the basic data and fundamental theoretical constraints on magmatic processes with applications to specific problems in igneous petrology. The Mineralogical Society of America (MSA) sponsored the short course on "Modern Methods of Igneous Petrolgy: Understanding Magmatic Processes" at the Cathedral Hill Hotel in San Francisco, California in December 1990. It was organized by the editors, Jim Nicholls and Kelly Russell, and presented by the authors of this volume to about 80 participants in conjunction with the Fall Meeting of the American Geophysical Union.