followed a unique path. The responding medical doctors have followed in the footsteps of Dominique Larrey, a military surgeon and the father of emergency medicine. For him, the on-scene presence of doctors is paramount to organise the entire healthcare and emergency response, an innovative method that has proven its efficacy. This book is intended for all healthcare and emergency staff, doctors, paramedics or first aiders in ambulances or in emergency services who might come to deal with a massive influx of injured, poisoned, or traumatised victims. The management of multiple concomitant emergencies requires specific know-how and skills. May this guide contribute to the dissemination of a validated French know-how and thus to save lives and alleviate suffering.