PolyARM Prehospital Handbook is a practical, concise guide for the multidisciplinary prehospital trauma team caring for critically injured and multiply-traumatised patients from the scene of injury to hospital handover. As the prehospital companion to the PolyARM Hospital Handbook, it covers on-scene assessment, field interventions, special populations, mass-casualty triage, and inter-team handover. Key points, alerts, action steps, and comparison tables present essential scores, thresholds, doses, and decision rules in an accessible format for rapid consultation in the field or during transport. The handbook is intended for emergency medical technicians, paramedics, prehospital and HEMS physicians, nurses, and trainees, and complements rather than replaces local EMS protocols and medical-direction policies.