Incarceration of women in the United States is at a historic high. Understanding women’s experiences in prison, their responses to treatment, their lives after prison, and how changing prison regimes have affected these things is limited. Individual attributes, pre-prison experiences, and prison conditions are associated with how women respond to incarceration. What is lacking in research is an assessment of their joint and conditional influences. Evaluations of interventions and studies of the long-term consequences of imprisonment are needed. Trends in and characteristics of women in prison in the United States, England and Wales, and Canada are outlined, focusing on the past two decades in an effort to understand women’s contribution to “the era of hyper-incarceration.” Work on women’s adaptations to and experiences of imprisonment is reviewed. This research draws from a variety of conceptual and analytical frameworks, including templates developed in the classic sociology of the prison of the 1940's and 1950's and more recent feminist analyses of women and social control. How imprisonment affects women’s lives after prison is discussed, including their chances of reoffending and the hurdles they face upon returning to their families and communities. Current work in penology and on women’s imprisonment is examined, highlighting and debating the significance of recent transformations in criminal punishment. Some directions for future research on women in prison and women’s imprisonment include the types of women that have been the primary targets of the imprisonment boom of the late 20th century. 3 figures, 3 tables, 60 footnotes, 264 references