Thirty-two years after “The Firm” launched his career as a legal novelist who churns out bestselling books that almost invariably become movies, John Grisham returns with a sequel starring Mitch McDeere. In “The Exchange,” it’s 2000 and McDeere is now a high-powered partner at the world’s largest law firm, Scully & Pershing, having “established a reputation as a sort of legal SWAT team leader sent in by Scully to rescue clients in distress.” He lives a very privileged life in Manhattan with his wife and two young boys. Grisham fans will love the first 37 pages, as McDeere travels back to Memphis for the first time since the events in “The Firm” and meets with an old friend.