"As Gib relives the previous day, he observes how every action has a consequence, an awareness that gives a thought-provoking philosophical edge to this accessible fantasy." – Horn Book Guide"[The Power of Un]'s themes and plot twists take it beyond the conventional, resulting in a delightfully thought-provoking science-fiction story." – School Library Journal"The author shares [Jerry] Spinelli's knack for writing hilarious dialogue that perfectly paints the funny, poignant, and altogether unpredictable world of eleven and twelve year olds. . . Etchemendy employs the familiar concept of time travel to create a unique, thought-provoking book that deserves a place on every middle school and public library shelf." – VOYA"Etchemendy's intriguing fantasy handles some powerful, big questions about life, the universe, and everything in it. . . . Gib tackles free will, memory, the bending of time, and contradictory impulses in a way that will sound fairly logical to middle-schoolers. . . This book deftly handles some eternal philosophical questions." – Booklist