After a long journey of inquiry into the history of movements and ideas for peace, we return again to the concept of pacifism, to consider its meaning and implications. In the nuclear realm pacifism is absolute, rejecting any use of weapons that are grossly destructive and inherently indiscriminate. In other dimensions of conflict, however, pacifism is conditional and pragmatic. It is predicated on a presumption against armed violence, but it acknowledges that the use of force, constrained by rigorous ethical standards, may be necessary at times for self-defense and the protection of the innocent. When understood in this “realistic” context, as Martin Luther King, Jr. phrased it, pacifism is not a term of opprobrium, after all. It is a word to describe movements, ideas, and practices for preventing war and building peace, just as intended by those who originally coined the term. It is part of a tradition dating back hundreds of years and originating in religious and philosophical principles that have evolved over thousands of years. This is not to deny the occasional inconsistencies of pacifism and the peace movement more broadly – a persistent naïveté, a tendency toward utopianism (perhaps evident in this volume), an inadequate grasp of the unavoidable dilemmas of security, an unwillingness to accept the inherent egoism of human communities – but these limitations do not detract from the status of pacifism as a legitimate social movement and scholarly discipline.