The aim of this 7-chapter, single-author textbook is to overview and illustrate pathological features of skin infections caused by bacteria, fungi, viruses, protozoa, helminth and arthropods with a total of 361 coloured figures. Histological features based on hematoxylin and eosin staining and gross appearance comprise the major part of the illustrations. Immunostaining using the indirect immunoperoxidase or amino acid polymer method and non-isotopic in situ hybridisation technique were employed when necessary. The indirect immunoperoxidase method using 1:500 to 1:1,000 diluted patients serum as a primary antibody was also applied to localize pathogens within the lesion fixed in 10-20% formalin and embedded in paraffin. Papanicolaou- or Giemsa-stained cytology evaluation, as well as electron microscopic analysis and polymerase chain reaction (PCR), were also performed upon request. The prompt and precise diagnosis of emerging and re-emerging infectious diseases, nosocomial infections and sexually transmitted infections has an important socio-public impact for the prevention of unnecessary transmission of micro-organisms. The skin may function as a mirror of internal organs. The author, as a diagnostic pathologist, sincerely hopes that this textbook helps pathologists, dermatologists and other clinicians make an appropriate diagnosis of skin infections. He strongly believes that the proper diagnosis may lead patients to proper treatment and cure, and may finally contribute to human society by preventing infectious disorders.