The good Doctor Dolittle, accompanied by his devoted animal friends, sets sail once again. This time it is a voyage of discovery, to learn the secret of the Shellfish language, and to teach Tommy Stubbins, the Doctor's young protégé, all there is to know about animals and their languages. The jolly party meets with more adventures than they had anticipated, including a shipwreck, a floating island, and a journey undersea in the Great Glass Sea-snail.

Winner of the Newbery Award for "the most distinguished contribution to children's literature in any single year."