Glucocorticoids (GC) are a class of steroid hormones that bind to the glucocorticoid receptor, which is present in almost every vertebrate animal cell. GCs are part of the feedback mechanism in the immune system that turns immune activity (inflammation) down. They are therefore used in medicine to treat diseases that are caused by an overactive immune system, such as allergies, asthma, and autoimmune diseases. GCs have many diverse effects, including potentially harmful side effects, and as a result are rarely sold over-the-counter. This book presents topical research from around the globe in the study of glucocorticoids, including the role of genetics in predicting glucocorticoid clinical response; the glucocorticoid receptor signalling in cancer and inflammation; the mechanisms of NO-redox imbalance in glucorticoid hypertension; and GCs in perioperative care.