The intrinsic properties of a solid, i. e., the properties that result from its specific structure, can be largely modified by crystallographic and chem ical defects. The formation of these defects is governed by the heat and mass transfer conditions which prevail on and near a crystal-nutrient in terface during crystallization. Hence, both the growth of highly perfect crystals and the preparation of samples having predetermined defect-induced (extrinsic) properties require a thorough understanding of the reaction and transport mechanisms that govern crystallization from vapors, solutions and...