The disorders which affect the brain and which are caused by an injury are treated within the field of brain injury medicine. It encompasses medical, physical, cognitive, sensory, and behavioral disorders. Acute injury refers to any severe injury that happens suddenly or spontaneously. Sudden injury to the brain is known as acute brain injury or traumatic brain injury (TBI). Alternatively, the death or degeneration of brain cells is known as neurotrauma or brain damage. Several internal and external events can cause brain damage. The severity of acute brain injury is estimated by determining how the normal brain function has been affected, the duration of loss of consciousness, the period of apnea (cessation of breathing), and the time it takes for the self-righting reflex to recover. An inflammatory response to TBI within the brain or spinal cord is known as neuroinflammation. It is caused by generation of cytokines, chemokines, reactive oxygen species (ROS), and secondary messengers. Neurodegeneration refers to the progressive atrophy (a condition in which a body portion, cell, organ, or other tissue shrinks in size) and loss of neuronal functions which is usually observed in neurodegenerative disorders like Alzheimer's and Parkinson's. The book aims to shed light on some of the unexplored aspects of brain injury. It will provide comprehensive knowledge with respect to the recent advancements in brain injury medicine.