Eugene Volokh has a few things to say about things that aren't supposed to be said. Volokh, a professor of free speech law at U.C.L.A., has seen books banned, professors censored, and the ordinary expression of students stifled on university campuses across the nation.

Volokh believes free speech and open inquiry, once paramount values of higher education, are increasingly jeopardized by restrictive university speech codes. Instead of formally banning speech, speech codes discourage broad categories of human expression. "Hate speech. Harassment. Micro-aggressions," Volokh says. "Often they're not defined. They're just assumed to be bad, assumed they're something we need to ban."

Edited by Todd Krainin.