A criminal history may provide more clues about future serious crime than has been appreciated in the past. Evidence of routine and low tariff crime have long been good predictors of future crime. The focus in predicting reconviction has been largely on the amount of crime that has been committed. An analysis of research encourages the notion that the type of crime that has been committed is also important in understanding the likelihood of future serious crime. Trying to probe the likely effect of changes of societal response to serious sexual assault by considering hypothetical models is a way forward to the challenge ahead of rethinking sexual crimes. It demonstrates that, as the reporting of serious sexual assault increases, the conviction rate needs to rise markedly to conquer a general feeling that matters are deteriorating rather than improving. The rise needed is much greater than most would have guessed. The question is whether the criminal careers of most sex offenders are really as short as some of the research suggests. The possible value of developing a social laboratory in a local area is suggested in order to begin to understand the changes over long periods of time in sex offenses. The dangers of “criminal apartheid” are highlighted. The major point is that there is still much to learn about sex crime. Ideas are developed following a systematic study of sex crime in one town, Lancaster, in the northwest of England, derived from the search of the local newspaper over a period of 120 years, 1860 through 1979. 14 notes, 4 figures, 13 references