Jonathan Cott’s new book There’s a Mystery There (Doubleday) is a terrific examination of what its subtitle calls “The Primal Vision of Maurice Sendak.” It accomplishes this by focusing on a single book, Sendak’s masterpiece, Outside Over There (1981), winner of a Caldecott Honor and a Boston Globe–Horn Book Award....

While marketed as a two-volume music CD with an accompanying booklet, Natalie Merchant’s Leave Your Sleep might be better understood as a fascinating anthology of children’s poetry accompanied by biographical notes and two CDs on which each of the twenty-six poems is set to music. But it is even more...