Mrs. What, Mrs. Who, Mrs Which. Screwy cherubim, mystical feathered pluralities, telepathic baby brothers. A dog named Fortinbras. And of course: tesseracts. What the hell am I talking about? The young adult books of Madeleine L’Engle (A Wrinkle in Time, A Wind in the Door, A Swiftly Tilting Planet) who passed away yesterday at the age of 88.