Today, picture books are everywhere. But in the 1800s, most children's books had few pictures, and the ones they did have were often dark and scary. Kate Greenaway, born on March 17, 1846, in London, changed that. She created a world of soft colors, sunny gardens, and children playing happily outdoors. Her illustrations showed an idealized version of childhood that people found irresistible. Her most famous book, "Under the Window," sold over 100,000 copies when it was published in 1879. That was an enormous number for a children's book at the time. Greenaway's art was so popular that it influenced fashion. Parents began dressing their children in the old-fashioned bonnets and dresses she drew. Her style even affected landscape gardening, as people tried to re-create the cottage gardens in her pictures. The art world took her seriously too. The famous art critic John Ruskin became her mentor and friend. Today, the Kate Greenaway Medal is one of the most prestigious awards in children's book illustration. It is given every year by the British library system to the best-illustrated children's book published in the United Kingdom.