Oxygen therapy is a treatment that provides a patient with extra oxygen to breathe in. It is also called supplemental oxygen. It is only available through a prescription from a health care provider. Patients may receive it in hospital, another medical setting, or at home. Some people only need it for a short period of time. Others will need long-term oxygen therapy. There are different types of devices that can provide oxygen. Some use tanks of liquid or gas oxygen. Others use an oxygen concentrator, which pulls oxygen out of the air. The oxygen is administered through a nose tube (cannula), a mask, or a tent. The extra oxygen is breathed in along with normal air. This book is a concise guide to oxygen therapy for clinicians and trainees. Divided into four sections the text begins with an overview of the basic facts of oxygen, describing the different types and their individual uses in clinical therapy. Section two discusses the physiology and monitoring of oxygen therapy, and section three covers different devices and delivery systems, and oxygen toxicity (lung damage from breathing in too much extra oxygen). The final section examines oxygen targets in disease specifics, how the therapy works, and the effects of hypoxia (low oxygen levels in body tissues) and hypoxemia (low oxygen levels in the blood).