Young Wemberly is a small mouse who worries about almost everything. “Wemberly worried about the tree in the front yard (What if it falls on our house?), and the crack in the living room wall (What if it gets bigger and something comes out of it?), and the noise the radiators made (What if there’s a snake inside?).” Her parents (who can’t help but worry about her) and her comically hip (“Go with the flow”) grandmother do their best to reassure her, but worrying just seems to be part of Wemberly’s nature. Wemberly’s newest worry is her biggest yet: she’s about to start preschool. This looming event generates a whole new list of worries for Wemberly. But her astute teacher, Mrs. Peachum, knows just what to do. He pairs Wemberly with the ideal classmate to make her first day of school a great success. Much of this book’s gentle humor is in the illustrations. The superbly paced narrative will leave children giggling at Wemberly’s worries but never laughing at Wemberly. Children know there is nothing funny about fear, and Henkes is masterful at illuminating real childhood concerns with humor without making light of them. One or more of Wemberly’s worries is sure to resonate with just about every young reader or listener. So while this is above all fine story-time entertainment, a little subtle reassurance is apt to be delivered along with the smiles. (Ages 3‑7)