DELIVERANCE by James Dickey. 278 pages. Houghton Mifflin. $5.95.
James Dickey's four characters seem far from ready for challenge or response. One is a quiet sales supervisor for a soft-drink company who not only believes in his company's product but in its advertising. Another sells mutual funds. Dickey's narrator, Ed Gentry, runs a Southern graphics studio cheerfully described as a "no-sweat shop." Just occasionally he is nudged by a fear of encroaching flab and a feeling that he is sliding too easily through life. Of them all, only Lewis Medlock seems outward-bound for the heart of darkness. At 38, he is...