This book is intended for post‐registration and post‐graduate level scientists who are developing careers in diagnostic clinical microbiology. It is suitable for those who are working in hospital laboratories while studying for advanced qualifications, as well as full‐time MSc students. The aim is to prompt readers to make connections between the clinical symptoms, pathogenesis of infections and the approaches used in laboratory diagnosis. This is not a comprehensive account of all aspects of clinical microbiology, but a consideration of a range of infections caused by selected pathogenic bacteria, viruses, fungi, protozoa and helminths. The idea is to use these examples to illustrate clinical and diagnostic issues, to stimulate critical appraisal of p idence and to encourage problem‐solving in the clinical laboratory context.