Dad by Christian Robinson; illus. by the author Preschool Balzer + Bray/Macmillan 48 pp. 5/26 9781250397041 $19.99 Fathers of all stripes, feathers, and species take center stage in this captivatingly illustrated, quietly complex picture book. “Dad is strong,” the book begins; the dad pictured is a formidable silverback gorilla, hulking across much of a double-page spread, his infant peeking up safely from beneath.