This interdisciplinary field investigates the homosexual—lesbian and gay—experience. Although a first wave of such research can be traced back to the late 19th century (notably the research of Magnus Hirschfield), the major contributions started to appear in the 1970s, in the wake of the rise of a lesbian and gay social movement. By the 1990s there were courses, institutes, conferences, and publishing houses which specialized in the area. Much of this work has been dominated by sociological research, particularly the ideas of Michel Foucault, and by the women's movement. See also heterosexism; homophobia; homosexuality.