In recognition of the trend toward problem-orientated learning in medical schools throughout Europe and the USA, the authors created this problem-based book in medical microbiology to complement the major textbooks in the field. The three authors are experienced teachers of medical students at the University of London, giving them a clear understanding of the requirements. They also have complimentary skills which together cover the entire field of medical microbiology, namely bacteriology, virology and parasitology. The book consists of a series of case presentations of a particular microbiological condition or pathological specimen. Each presentation consists of a photograph (many are in color) and a brief description of the signs and symptoms, and the results of relevant clinical investigations. The reader is then asked four questions, with the answers and key references provided on the facing page. The number of problems from each branch of the subject reflects their clinical importance and frequency in examinations. The major difference between this book and other similar ones is the level of detail given in the case descriptions and, more importantly, the answers and the selection of key reading references.