In Freudian Repression Michael Billig praises Freud for identifying the central concept of repression and for articulating his ideas in a clear and compelling way. In fact, he calls Freud "the greatest of all psychologists" (p. 261). But Billig points out, convincingly, that Freud never explained how repression works. Freud does offer metaphorical explanations, in terms of "censors" shielding one part of the self from threatening thoughts, but Billig argues that these explanations are both vague and conceptually unsatisfying.