Leprosy, also known as Hansen's disease, is an ancient disease retaining strong historic association with stigma. Almost everyone knows the word 'Leprosy' yet facts and fiction related to the disease are commonly confused. In spite of nearly three decades of intensive research into the immunology of leprosy, the mechanism by which M.leprae is able to elicit the entire range of human cellular immune responses has still not been explained. The spectrum of host response to M.leprae provides a model for investigating the role of a cytokine in the pathogenesis of mycobaterial disease. Ceramide, a major lipid in lipid bilayer is prevalent on nerve cells. This book will focus on the various aspect of immunological mechanism that contributes to the protection as well as pathological aspects of host response to leprosy. This book will also highlight the significance of anticeramide antibodies titre which could serve as a marker for nerve damage in leprosy.