Priscilla Cummingss Chadwick the Crab series has been a staple of Chesapeake juvenile literature for more than a decade. Now Ms. Cummings turns her hand to another classic genre, the ABC book, this one with a Chesapeake regional flavor. From A is for anchor to Z is for a zephyr, the sights, sounds, and feel of the Bay come through to the youngest of readers. This is a perfect way to introduce toddlers and preschoolers to the wonders of the alphabet and instill in them a love of the Chesapeake. (Also review its companion book, Chesapeake 1-2-3.) Whimsical drawings by David Aiken illustrate the verses about