The origin and development of the Head Injury Criterion (HIC) has been reviewed. The concept of correlating internal head injury with measured kinematics has also been re-examined. It is concluded that since no general kinematic correlation can be developed, the HIC concept is invalid. Recent attempts to develop relationships between head injury AIS and HIC, are shown to substantiate this view. Alternatives to HIC are reviewed and other approaches to head injury assessment are proposed.