The Tailor of Gloucester is a children's book written and illustrated by Beatrix Potter, privately printed by the author in 1902, and published in a trade edition by Frederick Warne & Co. in October 1903. The story is about a tailor whose work on a waistcoat is finished by the grateful mice he rescues from his cat and was based on a real world incident involving a tailor and his assistants. For years, Potter declared that of all her books it was her personal favourite.
A tailor in Gloucester sends his cat Simpkin to buy food and a twist of cherry-coloured silk to complete a waistcoat the mayor has commissioned for his wedding on Christmas morning. While Simpkin is gone, the tailor finds mice the cat has imprisoned under teacups. The mice are released and scamper away. When Simpkin returns and finds his mice gone, he hides the twist in anger.
The tailor falls ill and is unable to complete the waistcoat, but, upon returning to his shop, he is surprised to find the waistcoat finished. The work has been done by the grateful mice. However, one buttonhole remains unfinished because there was "no more twist!" Simpkin gives the tailor the twist to complete the work and the success of the waistcoat makes the tailor's fortune.