lincoln , professor emeritus of religion and culture at duke university in durham , n.c. , where he taught from 1976 to 1993 , wrote or edited more than 20 other books , including `` the avenue , clayton city , '' a novel published in 1988 , for which he won the lillian smith book award for best southern fiction , and a series of books in the 1970s called the c. eric lincoln series in black religion .