It is startling to realize how quickly and thoroughly the value of diversity, until a few decades ago a value largely confined to the aesthetic and organic realms, has acquired deep political and moral significance. Universities, corporations, and governments are now judged by the degree to which they achieve diversity among their leaders and recognize diversity among their publics. Older values of the liberal polity, for example that of honoring merit without regard to creed, race, sex, or ethnicity, have been increasingly eclipsed by values that closely attend to these and other differentiating traits (which traits matter is contentious). How did this sea change in value come about, and come about so swiftly? And what kind of value is diversity? The long history of diversity as an aesthetic and economic value helps explain the recent rapid rise of diversity as a moral and political value.