Mary O'Neill was an American poet and author, known for her contributions to children's literature and her lyrical poetry. Born in 1918, she published several collections of poetry, including The Book of the Sea and The Green Leaf. Her work often reflects themes of nature and childhood, making her a beloved figure in literary circles. In addition to her poetry, O'Neill was also an advocate for the arts and education. She served as a teacher and was involved in various literary organizations. Her influence continues to be felt in the realms of both poetry and children's literature, inspiring new generations of writers.