Multiculturalism emphasizes the unique characteristics of mulitplicity of cultures in the world, especially as the relate to one another in America.
Diane Ravitch identifies the two main currents of multiculturalism as pluralistic and particularist. Pluralistic multiculturalism views each culture or subculture in a society as contributing unique and valuable cultural aspects to the whole culture ("melting pot"). Particularist multiculturalism is more concerned with preserving the distinctions between cultures.
Particularists often deride Western Christendom in general or specifically America as narrowly "Eurocentric". For example, Edward Said's book Orientalism claims Westerners are inherently incapable of understanding Islam.
It is often difficult to distinguish the two currents Ravitch describes, as the celebration of a "diversity" can mask a hostility toward a mainstream which has ignored blacks, women, American Indians and so on in American history.