This chapter provides the opportunity to acknowledge this compatibility and to give shape to the informal collaboration that has existed for some years among the contributors and editors. It also provides an opportunity to consider the relationship between routine activity and rational choice and some other related theoretical and preventive approaches. The chapter discusses a fuller treatment of the relationship between these new approaches to crime and the traditional theories. The routine activity approach stated three minimal elements for direct-contact predatory crime: a likely offender, a suitable target, and the absence of a capable guardian against crime. The routine activity approach is fundamentally different from almost all other criminology in its intellectual roots, namely, the human ecology theory of Amos Hawley. While Shaw and McKay were human ecologists in the Chicago school and well-known in criminological literature, they worked mainly in the spatial dimension, plotting neighborhood structure and linking it to crime distributions.