Goodnight Moon's sales were slow at first

Margaret Wise Brown, author of Goodnight Moon and The Runaway Bunny, and Ursula Nordstrom, children's book editor at Harper, were born 3 months apart in 1910. They worked on several books (including the Runaway Bunny) before Goodnight Moon, which was published in 1947. They became good friends. Margaret died unexpectedly in 1952. It wasn't until after her death that Goodnight Moon became a runaway best seller.