This document discusses the history and techniques of cardiopulmonary resuscitation (CPR). It outlines the key stages of CPR: ensuring an open airway (A), providing artificial ventilation (B), and performing external cardiac massage to restore circulation (C). The main goals at each stage are described, such as tilting the head back to open the airway, giving two initial breaths and then 10-12 breaths per minute during ventilation, and compressing the chest at a rate of 80-100 times per minute during circulation. Drugs that can be administered during CPR like adrenaline, atropine, and lidocaine are also listed. The full algorithm of CPR involving cycles of compressions and breaths is