Thanatology is the academic, and often scientific, study of death among human beings. It also describes bodily changes that accompany death and the after-death period. The word is derived from the Greek language. In Greek mythology, Thanatos (meaning: “death”) is the personification of death. The English suffix—ology derived from the Greek suffix—logia (meaning: “speaking”). Thus, thanatology is a subject that deals with scientific study of death, types of death, the various events, or changes that occur in the cadaver after death and their medicolegal significance. In most of the countries of the world including India, there is no proper definition about death in law. However, Black’s Law Dictionary defines death as ‘the cessation of life’ while the Chamber’s Twentieth Century Dictionary, defines death as ‘the extinction of life’. Clinically death is defined as the irreversible cessation of life. Thus, physician declares death with cessation of all vital functions such as nervous, circulatory and respiratory systems. Death is a process not an event and, while the cells of some tissues are still alive and even capable of movement (such as fibroblasts, leucocytes and muscle fibres, etc.) others are dying or dead. Almost all doctors, whatever is their specialty, come across death at some time or the other in their profession. The legal and ethical aspects of this inevitable process form an important part of forensic medicine. For understanding more about death and its mechanism, it is considered under two heads, namely: (i) Somatic death and (ii) Molecular death. Somatic death is defined as the irreversible cessation of functioning of the brain, heart and lungs resulting in complete loss of sensibility and ability to move the body. Molecular death is defined as ultimate death of all cellular elements.