THE BODY IN THE LIBRARY -Agatha Christie -Dodd, Mead ($2). A female corpse discovered in the sanctum of an uxorious English colonel (retired) titillates the gossipy countryside, puzzles Scotland Yard no end, until Miss Marple, crown princess of spinster sleuths, takes an'unobtrusive hand. Genuine old-crusted Christie.
THE WIDENING STAIN-W. Bolingbroke Johnson-Knopf ($2.50). A sultry French teacher and an elderly classicist with a weather eye for women are violently extinguished in a U.S. university library. A girl cataloguer, playing a hunch, risks her life and traps a murderer with a peculiar motive. A capable...