With its enthusiastic jacket endorsement from Jonathan Franzen ("Alive with intelligence, comedy, and inside dope ... sure-handedly captures the uncertainties of our times") and its choice as a Book-of-the-Month Club selection, Mark Costello's Big If (Norton) would seem to be the promising debut of a terrific new American writer. But, as it happens, Big If is in fact the second novel by Mark Costello -- though only the first to bear his name.