Jihad is, or has come to be, a loaded term. Some in the West think it means holy war, an inherently violent notion; others say it means holy struggle, more a spiritual than a martial concept. This discussion dimly reflects the fact that even among educated Muslims the term has not always meant the same thing-this more so today than perhaps ever before. One reason that it is hard to pin down the idea of jihad is that it has an experiential base as well as a theological-juridical one, having been dragged through more than fourteen hundred years of history over an area stretching from Spain to Central Asia. Yet within this base of experience it retains a coherence sufficient to explain how most Muslims have thought about their own relations with non-Muslims and, increasingly, among themselves. This essay begins by laying out a theological and a historical synopsis of jihad, and then shows how the concept is being used today in various forms, and with various implications for Muslims and non-Muslims alike.