Book excerpt: The Undersea and Hyperbaric Medical Society (UHMS) is an international, non-profit organization serving over 2,400 members from more than 50 countries. The UHMS is the primary source of scientific information for diving and hyperbaric medicine physiology worldwide, the breadth of which is illustrated in the triennial report, Hyperbaric Oxygen Therapy Indications. With leading experts authoring chapters in their respective fields, this publication continues to provide the most current and up to date guidance and support for scientists and practitioners of hyperbaric oxygen therapy. Hyperbaric Oxygen Therapy Indications, currently in its thirteenth edition, has grown in size and depth to reflect the evolution of the literature on the approved use of hyperbarics from both a clinical practice standpoint and insurance coverage perspective. To date, the committee recognizes fourteen indications, including the new indication, idiopathic sudden sensorineural hearing loss. Additionally, this book continues to be used by the Centers for Medicare and Medicaid Services and other third party insurance carriers in determining payment for HBO2 services.