Next to having one's book prominently displayed on the racks of every airport bookstore in the country, receiving recognition for an article written more than half a century ago is a close second. Indeed, for some of us it is the very highest form of intellectual acknowledgment. The Shapley–Shubik power index, invented more than 50 years ago, is a familiar concept in the analytical lexicon of political science. In brief, it is a measure of the ex ante likelihood that an individual will be pivotal in transforming a nonwinning coalition into a winning one. This depends on the voting or decision rule, on the one hand, and on the number of votes or decision weight possessed by an individual, on the other. The “power” of an individual, so determined, may be aggregated to measure the power of a faction, party, proto-coalition, or voting chamber (the latter in a multicameral setting)