By Troy Patterson
Updated February 01, 2008 at 05:00 AM EST

In 1850, on the eastern shore of Maryland, a runaway slave named Liz tries to avoid capture by the rancid thief Patty Cannon and the somewhat more sympathetic Denwood Long. Liz entertains nightmares about ”the future of the colored race” that include premonitions of hip-hop beats (”a metallic bang-bang that pounded out of tiny boxes”), though the reader’s never sure what that has to do with anything else. Song Yet Sung, by James McBride, the author of the book-club staple The Color of Water, tends to spiral into irrelevance that way, undermining its textured take on history and its re-creation of how blacks aided fugitives. B