The book consists of three papers, "Beyond Tolerance" by Wolff, "Tolerance and the Scientific Outlook" by Moore, and "Repressive Tolerance" by Marcuse. In his contribution, Marcuse argues that the ideal of tolerance belongs to a liberal, democratic tradition that has become exhausted. Liberal society is based on a form of domination so subtle that the majority accept and even will their servitude. Marcuse believes that under such conditions tolerance as traditionally understood serves the cause of domination and that a new kind of tolerance is therefore needed: tolerance of the Left, subversion, and revolutionary violence, combined with intolerance of the Right, existing institutions, and opposition to socialism. Marcuse claims that tolerance shown to minority views in industrial societies is a deceit because such expressions cannot be effective. Freedom of speech is not a good in itself because it allows for the propagation of error; Marcuse believes that "The telos of tolerance is truth". Revolutionary minorities hold the truth and the majority has to be liberated from error by being re-educated in the truth by this minority. The revolutionary minority are entitled, Marcuse claims, to suppress rival and harmful opinions.
Writing in 1970, Maurice Cranston called A Critique of Pure Tolerance Marcuse's most popular and disturbing work to date. Cranston commented that the book was published, "in a peculiar format, bound in black like a prayer book or missal and perhaps designed to compete with The Thoughts of Chairman Mao as devotional reading at student sit-ins."Alasdair MacIntyre claims that Marcuse's theory of the right of revolutionary minorities to suppress opinions "is perhaps the most dangerous of all Marcuse's doctrines, for not only is what he asserts false, but his is a doctrine which if it were widely held would be an effective barrier to any rational progress and liberation". MacIntyre asserts that the telos of tolerance is not truth but rationality. It is a "necessary condition of rationality that a man shall formulate his beliefs in such a way that it is clear what evidence would be evidence against them" and that he should be open to criticism and have his opinions disproved in the light of any possible objection. MacIntyre claims that "to foreclose on tolerance is precisely to cut oneself off from such criticism and refutation. It is to gravely endanger one's own rationality by not admitting one's own fallibility".