This book is the first to detail the chemical changes that occur in deforming materials subjected to unequal compressions. While thermodynamics provides, at the macroscopic level, an excellent means of understanding and predicting the behavior of materials in equilibrium and non-equilibrium states, much less is understood about nonhydrostatic stress and interdiffusion at the chemical level. Little is known, for example, about the chemistry of a state resulting from a cylinder of deforming material being more strongly compressed along its length than radially, a state of non-equilibrium that remains no matter how ideal the cylinder''s condition in other respects. M. Brian Bayly here provides the outline of a comprehensive approach to gaining a simplified and unified understanding of such phenomena. The author''s perspective differs from those commonly found in the technical literature in that he emphasizes two little-used equations that allow for a description and clarification of viscous deformation at the chemical level. Written at a level that will be accessible to many non-specialists, this book requires only a fundamental understanding of elementary mathematics, the nonhydrostatic stress state, and chemical potential. Geochemists, petrologists, structural geologists, and materials scientists will find Chemical Change in Deforming Materials interesting and useful.