Maurice Sendak once said that the subject of all his work was the “extraordinary heroism of children in the face of . . . a mostly indifferent adult world.” Nowhere is this theme more lavishly treated than in Outside Over There (1981), the third — after Where the Wild Things Are (1963) and In the Night Kitchen (1970) — in a trilogy of fantasy quests. Like naughty Max and hungry Mickey, the hero of Outside Over There is a furious and resolute child. Her name is Ida, and she’s been left in charge of baby sister while Mama sits in the arbor, distracted by…