Convex bodies are at once simple and amazingly rich in structure. While the classical results go back many decades, during the past ten years the integral geometry of convex bodies has undergone a dramatic revitalization, brought about by the introduction of methods, results and, most importantly, new viewpoints, from probability theory, harmonic analysis and the geometry of finite-dimensional normed spaces. This collection arises from an MSRI program held in the Spring of 1996, involving researchers in classical convex geometry, geometric functional analysis, computational geometry, and related areas of harmonic analysis. It is representative of the best research in a very active field that brings together ideas from several major strands in mathematics.