Ib Spang Olsen was a Danish writer and illustrator best known to generations of Danes for cartoons and illustrations, many of which appeared in children's publications. Those include a series of nursery rhyme books written by Halfdan Rasmussen, including "Halfdans ABC". He also wrote his own children's books, such as the whimsical tale of the seasons, The Marsh Crone's Brew. Olsen drew for newspapers, magazines, books, posters, television, and comics. For his lasting contribution as a children's illustrator Olsen received the international Hans Christian Andersen Medal in 1972.