Book excerpt: This issue of Critical Care Clinics, Guest Edited by Dr. Rinaldo Bellomo, focuses on Modern Critical Care Endocrinology. Article topics include: Diabetes insipidus and SIADH in the ICU; Estrogen therapy in ICU patients; The angiotensin family, ACE and ACE 2; Angiotensin II in vasodilatory shock; Vasopressin in vasodilatory shock; Hydrocortisone in vasodilatory shock; Erythropoietin in trauma and critical illness; HbA1c and permissive hyperglycemia in diabetic ICU patients; Osteoporosis and the critically ill patient; New oral agents for the treatment of diabetes; Melatonin in critical care; The incretins in ICU patients; Hepcidin; Thyroid hormone therapy in the ICU; and Hormonal therapy in organ donors.