We read or write history in search of something from the past-be it insight, authority, or escape. For judges and other policy makers, especially those in the common law tradition, history is the most powerful source of political legitimacy. For conservative ideologues and other sentimentalists, the past reflects the best hope for the future. Academic and professional historians, more modest in their demands, seek only explanation. Yet, explanation has proved to be a contentious notion, a subject of longstanding debate among those who write about history. This essay is about current attitudes toward historical forms of explanation.