This textbook presents medical conditions as a one-page document with specific considerations regarding fitness-to-dive criteria. This is a portable and concise reference work for the busy medical examiner of divers. It will also provide invaluable background help for any medical practitioner who may be required to advise individuals who have questions concerning their health and diving activities. An extensive index will assist readers in finding what they want. Whilst this is neither a textbook of diving physiology nor a comprehensive account of hyperbaric medicine, it will be a valuable desk aid for all physicians who may have to consider medical fitness to dive. There are brief sections on a wide range of medical and surgical conditions which include a box detailing ‘absolute’, ‘relative’ or ‘no contraindications’. For example, in the section on hernias, absolute contraindications include hernias that are irreducible and painful, whilst a relative contraindication would be an asymptomatic hernia incipiens until repaired.