This atlas deals with conditions commonly encountered in the male genital tract. Whilst the majority of illustra tions are photomicrographs, photographs of macro scopic specimens are also used to illustrate important features in distinguishing different pathological con ditions. Special emphasis is placed on the small biopsy specimens obtained from prostate and testis in modern urological practice and the importance of clinico pathological co-operation in pathological practice is stressed. Recent advances in our knowledge of testicu lar tumours are discussed and illustrated. The text is not entirely descriptive and attempts to give an intellectual framework around which histopathological diagnosis in this field can be practised. A modest number of references are included; they have not been singled out as representing milestones in the development of our knowledge of these conditions - the choice has rather more centred upon recent reports from which a litera ture search can be mounted if required. The atlas in no way pretends to be an encyclopaedic reference of con ditions of the male genital tract but attempts to provide an up-to-date comprehensive discussion of the histo pathology of this system. Acknowledgements I am most grateful to Mr Keith Gordon for developing all the photomicrographs and to Mr Geoff Gilbert and his staff in the Audio-Visual Department of the City Hospital who took the majority of the macroscopic illustrations. I must particularly thank my secretary, Mrs Dorothy Clay ton, for typing and retyping my draft chapters and for deciphering my hieroglyphics.