Award-winning American children's book author and Illustrator who is best known for her novel The Westing Game, published in 1978. She illustrated over 28 books between 1956 and 1970.
She grew up during the Great Depression and went on to attend the University of Wisconsin–Madison.
She won two Newberry Medals, one in 1975 for Figgs and Phantoms and another in 1979 for The Westing Game.
She married Dennis Flanagan, the Editor of Scientific American, in 1965.
Among the book covers she designed was the original cover of Madeline L'Engle's A Wrinkle in Time.
