Britta Kyvsgaard examines the nature of the "criminal career" through her longitudinal analysis of 45,000 Danish offenders. The data, unparalleled in size and quality, allows the accurate analysis of criminal behavior, even among relatively small demographic subgroups. Kyvsgaard determines offending patterns for males and females, juveniles and middle-aged adults, and employed and unemployed individuals. Furthermore, she examines the effects of deterrence and incapacitation. Her findings suggest that rehabilitation is worthy of further research.