It was on the rocks of efficiency that antitrust of the sixties foundered. This concern is even greater today. It is not enough simply to return to legal reasoning. The policy that results is not acceptable simply because the tools used in its formulation are those known to lawyers. I suggest that courts have been led to the use of economic policy through precisely the methods that Professors Flynn and Ponsoldt applaud. The critical question for the future is the substance of antitrust policy. The failure to consider the costs that a given policy imposes will virtually assure its failure. A multivalued antitrust policy that does not adequately deal with efficiency claims cannot, and should not, command broad acceptance.