Book reviews : The Norton Anthology of African American Literature Edited by HENRY LOUIS GATES JR and NELLIE MCKAY (New York and London, W.W. Norton & Company, 1997). 2,665 pp.  21.00 / The Oxford Companion to African American Literature Edited by WILLIAM L. ANDREWS, FRANCES SMITH FOSTER and TRUDIER HARRIS (New York and Oxford, Oxford University Press, 1997). 886pp.  35.00. / The Oxford Book of the American South Edited by EDWARD L. AYERS and BRADLEY C. MITTENDORF (New York and Oxford, Oxford University Press, 1997). 597pp.  22.50