Matthew (white) and Tilly (black) do everything together until Matthew accidentally breaks one of Tilly's crayons. Their tiff lasts until both are lonely; then they apologize and make up. The story is slight (though its meaning is large), but it's told perceptively and with grace. Peck's rather dark illustrations use rich, soft color and rough impressionistic forms to evoke the somber interiors and well-worn streets of an old N.Y.C. neighborhood (Washington Heights, according to the jacket). Most interesting for its beautifully observed illustrations, a sympathetic (but not particularly original) portrayal of one of friendship's typical vicissitudes.