when confronted with broadly similar problems, countries having similar economic organisation and general cultural backgrounds have chosen rather different waste management regimes. these differences extend to the institutional framework selected, the technology used, and the processes through which the regimes have been developed. how can one make sense of these differences? beyond standard economic assumptions that choice can be explained solely in terms of the selection of the best cost-benefit ratios, the study of waste management reveals that social choice depends on the way that political processes and institutional mechanisms combine the heterogeneous rationales that co-exist in western societies. describing change in terms of regimes, institutional parameters and policies raises the question of how change is introduced. in europe, this also includes the context of the european single market. should there be free mobility of waste within the eu? the five case studies presented here reveal a panorama of national regimes contemplating different development options within their own institutional trajectories. differences, however, can be reduced to the interplay of only a few variables, as is done in the concluding chapter.