Orthostatic intolerance (OI) describes a group of circulatory disorders whose symptoms are characterized by a dramatic drop in blood flow to the brain when people sit down or stand up. It is often associated with other acute issues, such as substantial drops in blood pressure, tachycardia, dizziness, and fainting, or long-term problems, such as chronic fatigue, fibromyalgia, and "long COVID." Living Well with Orthostatic Intolerance is an indispensable guide for those diagnosed with the disorder, their families, and physicians.