Book excerpt: British Medical Association Book Awards 2009 - First Prize Winner, Primary Care Category Evidence-Based Diagnosis in Primary Care provides guidance on diagnosis in general practice, from the patient’s first presentation with a symptom to the final establishment of a diagnosis or referral for further investigation. The book is divided into two parts: • Symptoms; which details the steps necessary to reach a provisional diagnosis when a patient presents; and • Disorders; in which the more detailed assessment of that initial diagnosis is described. This is the first book to be written about diagnosis in primary care that attempts to base its guidance on the research evidence. Enough information is provided on each symptom, or condition, to decide on the pre-test probability of each possible disorder, and how the symptoms, signs and investigations alter those probabilities to allow a conclusion to be reached about the most likely diagnosis. Evidence-Based Diagnosis in Primary Care also explains the principles of evidence-based diagnosis – with special emphasis on the issues raised by attempting an evidence-based approach in primary care – and clearly demonstrates the power, and the difficulties, of an evidence-based approach. Many chapters also feature ‘red flags’ – elements of the history or examination that should alert the practitioner to the possibility of serious disease, which is vital for general practice.