"The reviewer, like other kinds of writers, has his ego; and, since he is continually occupied with other people's books, it is somewhat peculiarly difficult for this ego to assert itself.  One of the best ways in which a reviewer can give himself a vicarious sense of creation is by encouraging and presenting new writers who have previously been unknown, but when a writer is already known, the reviewer may procure the sensation of power by making the gesture of putting him down.  This psychology must always be reckoned with. In the literary world in the last few years, one has seen a number of writers cried up at the time when they were still obscure, by the more discerning critics, and then afterwards disparaged by them."
-- Edmund Wilson