Dermatology is the science responsible for the study of the skin, mucous membranes (oral and genital) and cutaneous appendages, while dermatopathology focuses on its microscopic study. Although the two fields are closely related, in many cases the identification of dermatological diseases is mainly clinical and depends on the physician’s ability and experience. The purpose of this atlas, which collects over 900 clinical and histological photographs in high resolution, is to illustrate and describe the most frequent skin diseases on the basis of clinical cases. Offering a complete guide to the etiology, epidemiology, clinical features, histologic findings and diagnosis of the main skin diseases divided into three subgroups (inflammatory, infectious, or tumoral), it represents an invaluable resource for all medical students, residents, clinicians, and investigators learning dermatology.