This book intends to investigate the broad spectrum of genetic changes in immunological processes involved in cutaneous diseases. One of the main goals of immunogenetic studies is finding susceptibility genes for complex diseases. This can provide an insight into the pathogenesis of the condition in a way that is not easily achievable through other kinds of studies. Thus they are a rational initial step for generating hypotheses about disease pathogenesis. This may especially benefit dermatology, a field notorious for having too many diseases with unknown etiologies. Immunogenetic investigations have made targeted treatment strategies possible for diseases such as psoriasis and pemphigus. Even though these strategies have revolutionized the management of chronic dermatological conditions such as psoriasis, still there are a lot of unanswered questions. For instance, psoriasis patients respond very differently to each of the commercially available biological agents. This diversity could be partially explained by the differences in the sets of genes responsible for disease induction in each individual. Thus whole genome sequencing strategies, if feasible at individual levels, might help in tailoring these targeted treatments based on specific genetic backgrounds. Our intention in preparing this book was to explore the broad spectrum of the genetic aspects of immunological processes involved in cutaneous diseases. We have tried to cover most areas of dermatology where enough studies were available to gather a chapter. Still, there is a substantial lack of knowledge on the immunogenetics of many dermatological conditions. We hope that this book would encourage the investigators to fill these gaps of knowledge.