All Creatures Great and Small is a British television series made by the BBC and based on the books of the British veterinary surgeon Alf Wight, who wrote under the pseudonym James Herriot. Set in the Yorkshire Dales and beginning in the mid-1930s, it stars Christopher Timothy as Herriot, Robert Hardy as Siegfried Farnon, the proprietor of the Skeldale House surgery, and Peter Davison as Siegfried's "little brother", Tristan. Herriot's wife, Helen, was initially played by Carol Drinkwater and in the later series by Lynda Bellingham.

Wallace Brian Vaughan Sinclair was a British veterinary surgeon who worked for a time with his older brother Donald, and Donald's business partner, Alf Wight. Wight wrote a series of semi-autobiographical novels under the pen name James Herriot, with Sinclair and Donald appearing in fictional form as brothers Tristan and Siegfried Farnon. The novels were adapted in two films and television series under the name All Creatures Great and Small. Tristan was portrayed as a charming rogue who was still studying veterinary medicine in the early books, constantly having to re-take examinations because of his lack of application, often found in the pub, and provoking tirades from his bombastic elder brother Siegfried.