Successful injury control measures (stoplights, sprinkler systems, electrical insulation, evacuation) have long been commonplace. However, progress in injury control has been hampered by the failure to recognize that injuries cannot occur without the action of specific agents analogous to those of the infectious diseases and likewise transmitted by vehicles and vectors. These agents are the several forms of injury. Varying and interacting with the characteristics of the host and the environment, they constitute the classic epidemiologic triads that determine injury distributions, none of which are random. The injury-disease dichotomy, a universal in most of the world's major languages, may have resulted from the fact that at least some of the causes of injuries (for example, wild animals or falling trees) are more identifiable and proximate than the causes of diseases. The etiology of injuries suggests that for epidemiologic and public health purposes, the term injury should probably be defined so as to encompass those kinds of damage to the body that are produced by energy exchanges and that are manifested within 48 hours, or usually within considerably shorter periods. Strategies for injury control can be extended to the control of other pathological conditions. The active-passive distinction (the dimension expressing the extent to which control measures require people to do something) has a direct bearing on the success of public health programs, because passive approaches have historically had a far better record of success than active ones. Ten basic strategies have been identified that provide options for reducing the damage to people (and property) caused by all kinds of environmental hazards.