In my lifetime, academic freedom has been repeatedly under threat. In the 1950s, in the McCarthy era, hundreds of teachers were interrogated about their political beliefs and summarily fired, whether or not those beliefs had anything to do with the subject matter they taught. In the 1990s, “political correctness” was the term used by conservative critics of the university to attack the results of affirmative action and the subsequent increased diversity of students, faculty, and the curriculum. The first essay I wrote on the subject of academic freedom was for a series of lectures sponsored by the American Association of University Professors and subsequently published in 1996 in a book edited by Louis Menand. His introduction sought to reply to those who had denounced “multiculturalism” and “postmodernism” as philosophies that were antithetical to the truth-seeking project of the academy. He argued, as many of us did in our essays, that the presence of once-excluded groups in the university (women, African Americans, gays, and lesbians) required new forms of knowledge production; indeed, we pointed out that the supposed objectivity of an earlier curriculum was often a mask for entrenched patterns of discrimination. Challenges to disciplinary orthodoxies need not be violations of academic freedom, we insisted, but—when pursued with rigor and scholarly seriousness—were precisely exercises of that freedom. The success of the new programs, and their widespread adoption, is testimony to the ways in which academic freedom can at once preserve the integrity of scholarship and enable dramatic expansion of what counts as legitimate knowledge.