Given the substantial influence that the Global Polio Eradication Initiative can be expected to have on future eradication initiatives, it seems increasingly important to identify and analyze lessons from each phase of this program. The protracted "tail" of the polio eradication initiative currently appears to be disproportionately influencing discussion of, and decisions on, future eradication efforts, particularly with respect to the potential merits of a future measles eradication effort. Consequently, for the purposes of this chapter the "late stages" of the polio initiative have been analyzed, with most attention to those geographical areas that have never interrupted wild poliovirus transmission and those which have been regularly reinfected. The major lessons that have been identified might be applied earlier in future eradication initiatives, ultimately increasing the prospects for their launch, early scale-up, and successful conclusion. The most pertinent lessons identified were in assessing operational feasibility, sustaining and applying research, conducting effective advocacy at the subnational level, operating in insecure areas, and anticipating and addressing vulnerabilities in areas with especially weak health systems.