The book "System of practical medicine. Edition of American authors. Volume 4: Diseases of the urinary cavity and skin systems. Medical ophthalmology and otolaryngology" is an updated and detailed instruction for doctors working in the field of medicine. This part of the book explores a wide range of diseases related to the genitals, urinary system, skin, eyes and ears. Thanks to the unique approach of American specialists to the topic, the book provides the reader with comprehensive information about modern methods of diagnosis, treatment and prevention of these diseases. The publication will be useful both for professionals in the field of medicine and for a wide range of readers who are interested in issues of health preservation and treatment of various diseases.