Mary O'Neill was an American children's author, poet, and advertising copywriter best known for Hailstones and Halibut Bones, a celebrated collection of poems exploring colors through verse. After studying at Western Reserve University and the University of Michigan, she worked in advertising before becoming a full-time writer. Her books include People I'd Like to Keep, Saints: Adventures in Courage, and Words Words Words. Following her husband's death, she taught writing with the Peace Corps in Ghana and Costa Rica before her death in 1990.