Is there such a thing as forbidden knowledge? Are some ideas too dangerous for members of a society to handle? This is the idea behind book banning and censorship, methods meant to create a degree of social control by restricting access to ideas or art or other kinds of expression. Recently, American conservatives have been engaging in this activity again in an effort to limit access to information about race relations, gender politics, and sexuality. Drawing from recent journalism and political writing, this volume of The Reference Shelf looks at the political debate and the social movements behind this resurgence in authoritarianism.