The simplest and most disarming of three attractive new entries, all about domestic animals, in the Read and Wonder series. Dogs are introduced here on lively endpapers depicting individuals from nine breeds plus Rover ``the mongrel'' and Wendy ``the other mongrel''; the subsequent text consists solely of significant verbs (e.g., ``sniff''; ``piddle''; ``drool''; ``chase''; ``pant''; ``gnaw''; and of course ``wag'') captioning lively spreads of the dogs in characteristic activities, as a gregarious group in the park or back home where a litter of labs snuggles up to Wendy while their mother naps. Firth conveys an enormous amount about dogs' preoccupations and behavior in sharply observed illustrations that are wonderfully ebullient and entertaining. Hansard's A Field Full of Horses (ISBN: 1-56402- 302-8) is more staid but also conveys a surprising amount with just a few more simple words and Kenneth Lilly's realistic art, while Karen Wallace's My Hen Is Dancing (ISBN: 1-56402-303-6, illustrated by Anita Jeram) is a touch whimsical but equally informative (given that this is a free-range bird on a small British farm). All three are fine early informational books; Wag Wag Wag is outstanding. (Nonfiction/Picture book. 2-7)