This is a children's book based on the legend surrounding Richard Whittington. Whittington, who died in 1423, was mayor of London 1397-1399, 1406-1407, and 1419-1420. He became very prosperous and generous. The legend says that he was a homeless boy who did odd jobs in a house and kept a cat to keep the rats away. But, he had to send the cat off on a trading ship. The cat was sold to a Moorish ruler whose kingdom had been overrun with rats. The cat becomes a noted ratter and the ruler bestows a great treasure on Whittington. (However, the historical Whittington appears to have been the son of a knight of Gloucester). The earliest known appearance of the legend is in 1605. This book was a 1951 Caldecott Honor book (i.e., a runner-up to the Medal winner) for best illustration in a book for children. I've always found it of interest to discover how much children enjoy stories that are based on real people.