The first study focuses on the introduction of imprisonment in Sweden in the early 19th Century. In this process, four developments were significant: the acceptance of individual freedom as a social value, the relation between penal and educational goals, the reorganization of the criminal justice system, and the concurrent expansion of numerous other institutions. The second study questions whether general deterrence can be empirically tested. Using Swedish theft conviction data (1841 to 1990) and reported theft data in Stockholm (1866 to 1990), it argues that a time series approach presents theoretical and empirical problems. The author shifts the focus from observing annual variations to secular trends and interruption of trends, and from deterrent effects on individuals to aggregated effects of the administration of justice. The results do not substantially support the general deterrence hypothesis in a longitudinal perspective. The third contribution criticizes a recent Swedish study on general incapacitating effects, which stressed the negative impact of the 1983 penal reform. After the reform, most inmates are eligible for parole after serving only half of their sentence. The author concludes that the previous study exaggerated the negative effects of the conditional release. Each study includes numerous bibliographical references and statistics.