Mosaicism is a powerful biologic concept, originally developed from studying plants and animals. All cutaneous neoplasms, both benign and malignant, reflect mosaicism, which is the necessary basis to explain numerous human skin disorders. For example, various mosaic patterns visualize the embryonic development of human skin and X-linked skin disorders explain why women live longer than men, and so on. This book presents, for the first time, a comprehensive overview on the strikingly manifold patterns and peculiarities of mosaic skin disorders. This reader-friendly structured and straightforward publication will help the dermatologist to understand the underlying molecular mechanisms of skin disorders in order to further improve the treatment outcome.