Introductory note: This chapter examines the requirement that the defendant's actus reus must have “caused” the harmful result. The prosecutor must make two distinct showings of causation: (1) that the act was the “cause in fact” of the harm; and (2) that the act was the “proximate” or “legal” cause of the harm. Problems like that of the unintended victim, or the intervening act, fall within category (2).