This publication, Training Circular TC 4-02.1 First Aid including changes 1 and 2 December 2018, provides first aid techniques and guidance for Soldiers. Implementation of the techniques presented in this publication enable Soldiers to render first aid and prevent greater harm to injured Soldiers. The principal audience for TC 4-02.1 is commanders, subordinate leaders, individual Soldiers, Department of Defense (DOD) civilians and contractors. Because medical personnel will not always be readily available, nonmedical Soldiers must rely on themselves and other Soldiers' skills and knowledge of first aid methods to render aid until medical assistance arrives. First aid is given until medical care provided by medically trained personnel such as a combat medic or other health care provider arrives. The individual being provided first aid (by self-aid, buddy aid, or combat lifesaver) is considered a casualty. Once medically trained personnel (combat medic, paramedic, or other health care provider) initiates care, the casualty is then considered to be a patient. Training Circular 4-02.1 provides first aid procedures for nonmedical personnel in environments from home station to combat situations. This publication is meant to be used by trainers and individuals being trained based on common first aid tasks. Tasks are found in the Soldier's Manual of Common Tasks, Warrior Skills Level 1, and appropriate modified tasks from the Soldier's Manual and Trainer's Guide, Military Occupational Specialty (MOS) 68W. These tasks are meant to reinforce and maintain proficiency in correct procedures for giving first aid throughout a Soldier's time in Service. Training Circular 4-02.1 is designed to facilitate training and first aid competencies by bridging first aid training across the spectrum of assignments from training to permanent duty station and deployment. Tactical combat casualty care (TC3) is introduced in TC 4-02.1 with first aid tasks and procedures associated with combat situations. Individual and multiple first aid tasks in combination with collective tasks, may be integrated into various training scenarios.