This handbook on Understanding medical error by the Karachi Bioethics Group addresses an important but taboo topic in healthcare. It is a slim manual of 53 pages intended to shed light on identifying, managing and minimising medical error. The dictum oft quoted in medicine 'primum non nocere' is just the beginning. The complexity and demands of the current healthcare system make this dictum grossly inadequate to describe what is expected of a physician today. The booklet is especially relevant in the current atmosphere of distrust which surrounds the medical profession.