Which 1963 children's book by Maurice Sendak was sometimes banned for its dark themes?

The 1963 children's book by Maurice Sendak that was sometimes banned for its dark themes is Where the Wild Things Are.

The picture book follows Max, a boy who wears a wolf suit, causes havoc at home, and is sent to bed without supper. His imagination transforms his room into a wilderness where he meets the Wild Things, becomes their king, and eventually returns home to find his supper waiting for him.

Some adults initially considered the book frightening or inappropriate for young children because of its angry child protagonist, monstrous creatures, threats, and emotional intensity. These reactions led to restrictions and challenges in some libraries and schools. Sendak, however, treated children's anger, fear, jealousy, and frustration as real emotions rather than subjects that should be hidden from them.

The Wild Things were partly inspired by Sendak's relatives, whom he caricatured in the illustrations. He originally planned a story about “wild horses,” but changed them after realizing he did not know how to draw horses. The book won the Caldecott Medal in 1964 and helped redefine what a serious picture book could explore.