Given Hovenkamp’s influence and intellect, the publication of The Antitrust Enterprise is a major event, particularly since he sets out, according to the book’s jacket, to provide “the first authoritative and compact exposition of antitrust law since Robert Bork’s classic The Antitrust Paradox was published more than thirty years ago.” Nevertheless, one could quibble with the jacket’s claim. Richard Posner substantially updated his own authoritative and compact exposition of antitrust law in 2001. In a 2003 book review, Hovenkamp called Posner’s second edition a “marvelous and important book.” So, before beginning a review of Hovenkamp’s new work, it seems necessary to address the question of why we need another such treatment four years later. The answer is that Hovenkamp’s goal is very different from that of Posner and Bork. Posner and Bork wrote what Hovenkamp calls “polemical works” against the prevailing antitrust regime (p. 37). In the 1970s the prevailing regime was highly interventionist, suspicious of all manner of horizontal and vertical restraints and mergers, and intent on protecting small business from larger rivals, regardless of the cost to consumers. Bork and Posner’s “polemical” works attacked the entire edifice of antitrust reasoning that had prevailed since the second half of the New Deal. By 2001, Posner had seen much of his revolutionary vision come to fruition, but his second edition retained its attacks on the Warren Court’s antitrust policies just in case anyone was tempted to turn back the clock. Hovenkamp has no such revolutionary ambition.