The remit for the first edition of the ABC of Dermatology in 1987 was that it should concentrate on common conditions and give down to earth advice. The ABC format proved well suited for this and there has been a steady demand for the book since then. In this edition the same approach is maintained while taking into account advances in diagnosis and treatment. Research in genetics and immunology is providing ever-increasing insights into the mechanisms that underlie clinical changes, and has led to more accurate diagnosis and more rational treatment. Specialised techniques that may not be relevant to common conditions can be of the.