Book excerpt: For nearly a century, French's Index of Differential Diagnosis has been unparalleled in providing the clinician with invaluable assistance in quickly and correctly diagnosing a disease from a whole range of presenting symptoms. Arranged alphabetically by symptom, the text helps readers identify each presentation, describes the different diagnoses that it could represent, and explains the signs and tests used to make a diagnosis. Colour photographs of the highest quality have been included to help aid diagnosis at a glance. Highlights: Completely updated and revised with contributions from key clinical specialists More than 600 high-quality photographs to aid rapid diagnosis Clear presentation and well-organised text with alphabetical structure, allowing instant access to information Differential diagnoses presented in clear lists and tables to aid rapid reference The fifteenth edition of this essential text offers a succinct and well-illustrated aide-memoire that will be indispensable to trainee and established doctors in both general and hospital practice, as well as an invaluable reference for medical students.