Research will never answer the question of whether the vastly increased use of imprisonment has substantially enhanced public safety. Rising crime rates may affect imprisonment rates, or rising imprisonment may affect crime rate, or both may be affected by something else. Disagreement exists about the reasons for both recent and past changes in crime patterns. However, imprisonment policies beginning in the 1970's leapt far ahead of knowledge about prisons and prisoners. Important research has been conducted on prisons and prison-related issues despite limited funding for corrections research. Research has aided understanding of several issue clusters. One issue cluster involves the collateral effects of imprisonment on prisoners' coping in prison, on their later lives, on their later physical and mental health, on their families, on their recidivism, and on the larger community. Additional issue clusters include the crime control effects of imprisonment; inmate and staff subcultures and interactions; and the political economy of prisons. Further research could further aid understanding of imprisonment and related corrections issues. 63 references