Bow-Wow Birthday (32 pp.; $14.95; Feb.; 1-56397-489-4): Young Maris throws the grizzled dog, Rambler, a 100th (in dog years) birthday party, but while she and her friends energetically bicker and chow down, he disappears. Where has he gone? In page- filling pastels, Johnson-Petrov creates a lighthearted contrast between Maris, with her dramatic gestures and flyaway red hair, and Rambler, stiffly moving on aging bones from one nap to the next. Maris's friends appear to be so obnoxious that the party can't possibly be that much fun, but the warmth between child and dog will make readers smile. (Picture book. 5-8)