There is a common perception that the criminal behavior of women and the delinquent behavior of girls are not serious problems. Women are more likely to commit minor offenses and have historically constituted a very small proportion of the offender population. But these facts mask a trend that is beginning to attract attention. The dramatic rise in the number of prison and jail inmates is fairly well known; less so is that the ranks of women inmates are increasing much faster than those of their male counterparts. The pace at which women are being convicted of serious offenses is picking up faster than the pace at which men are convicted. These dynamics make the papers on women and girls in the justice system, presented here, especially timely. What animates the studies is not so much numbers of offenders but the particular circumstances of the women and girls "behind" the numbers. The authors call for "redefining justice," the theme of the plenary session at which their papers were presented, to take these circumstances into account. Whether justice should promote unalloyed equity, be blind to the circumstances in which crime is committed, and consider only gravity of offense and prior record, is still a matter of debate. In the current sentencing environment, the view of those who favor equity above all other considerations has won the day. There is another perspective-the belief that sanctions ought to be tailored to the specific characteristics and circumstances of individual offenders. Implicit in the three papers is the suggestion that gender is a special consideration warranting differential treatment. The writers amply demonstrate that women and girls who are caught up in the justice system enter it as a result of circumstances distinctly different from those of men, and so find themselves at a distinct disadvantage. Research as a tool to enhance policy and practice was the theme of the 1999 Conference on Criminal Justice Research and Evaluation, from which these papers were drawn. The papers reveal the real-life implications of research for a situation of growing urgency. They show that studies have uncovered a link between the victimization of women and their criminal behavior and they propose that justice system practice can be enhanced if policymakers and the practitioners who operationalize their decisions redefine justice to take this special condition into account.