The wide range of case studies presented in this book demonstrates that microliths have been selected in many different contexts to solve a number of different problems. Focusing on variability rather than homogeneity provides a useful way to learn how general processes operate in unique, historically contingent cases. Cost/benefit modeling demonstrates that artifacts with side-hafted microliths are relatively expensive in time, energy, and raw material expenditure and are therefore only likely to have been adopted when the costs of failure were quite high. These tools may also have been selected because of their potential to satisfy a range of needs, and the gains from a multipurpose solution could have offset the costs. In contrast, in situations in which risks were low, end-hafted microliths may have been used. Finally, historical trajectories should be considered as an important factor in the adoption, expansion, and preservation of particular patterns of behavior.