There are many texts and handbooks available describing tribological processes, effects of additives on lubrication, tribochemistry, surface engineering, and heat treating methodologies involved in surface modification. However, few of these texts provide a thorough integration of surface modification reactions and processes to achieve a tribological result and none provides a physical tribochemical (mechanistic) understanding of surface structural changes that occur under various circumstances. This book was written to address these deficiencies and provide a critically important text for this vitally important technology field.