In his books, Wight calls the town where Herriot lives and works Darrowby, which he based largely on the towns of Thirsk and Sowerby. He also renamed Donald Sinclair and his brother Brian Sinclair as Siegfried and Tristan Farnon, respectively, and used the name "Helen Alderson" for Joan Danbury.
Contrary to popular belief, Wight's books are only partially autobiographical, with many of the stories being only loosely based on real events or people. Wight's son, Jim, states that a lot of the stories, although set in the 1930s, 1940s or 1950s in the books, were actually inspired by cases that Wight attended in the 1960s and 1970s.
From a historical standpoint, the stories help document a transitional period in the veterinary industry; agriculture was moving from the traditional use of beasts of burden (in Britain, primarily the draught horse) to reliance upon the mechanical tractor and medical science was just on the cusp of discovering the antibiotics and other drugs that eliminated many of the ancient remedies still in use. These and other sociological factors, like increased affluence, prompted a large-scale shift in veterinary practice over the course of the 20th century; at its start, virtually all of a vet's time was spent working with large animals: horses (motive power in both town and country), cattle, sheep, goats and pigs. By the year 2000, the majority of vets practised mostly on dogs, cats, and other pets belonging to a population having a larger disposable income, people who could afford, and had the leisure time, to keep animals merely for pleasure. Wight (as Herriot) occasionally steps out of his narrative to comment, with the benefit of hindsight, on the primitive state of veterinary medicine at the time of the story he is relating; for example, he describes his first hysterectomy on a cat and his first (almost disastrous) Caesarean section on a cow.
The Herriot books are described often as "animal stories", (Wight himself was known to refer to them as his "little cat-and-dog stories".) and given that they are about the life of a country veterinarian, animals certainly play a significant role in most of the stories. Yet animals play a lesser, sometimes even a negligible, role in many of Wight's tales: the overall theme of his stories is Yorkshire country life, with its people and their animals as primary elements, which provide their distinct character. Furthermore, it is Wight's shrewd observations of persons, animals, and their close inter-relationship, which give his writing much of its flavour. Wight was just as interested in their owners as he was in his patients and his writing is, at root, an amiable but keen comment on the human condition. The Yorkshire animals provide the elements of pain and drama; the role of their owners is to feel and express joy, sadness, and, sometimes, triumph.
The books have been adapted for film and television, including a 1975 film titled All Creatures Great and Small, sequelled by 1976 It Shouldn't Happen to a Vet, and a long-running BBC television programme of the same title.
At the time of his death, the Reader's Digest Condensed Book volume containing All Creatures Great And Small (Volume 96, 1973 #5) was the most popular book in that series' history. His last book, Every Living Thing, immediately went into the top 10 best-seller list in Britain, and had an 865,000 copy first edition printing in the United States.
Herriot's fame has generated a thriving tourist economy in Thirsk. Local businesses include the "World of James Herriot" museum (located at 23 Kirkgate, the original practice surgery) and a pub at one time called the "Darrowby Inn", which was later renamed. Many of the original contents of his surgery can be found at the Yorkshire Museum of Farming in Murton, York. Parts of the BBC TV series set, including the living room and the dispensary (see picture, right), are on display at the James Herriot museum in Thirsk, which is also open to the public.
In 2010 the BBC commissioned a three-part drama called Young James Herriot for the BBC, inspired by the true story of James Herriot/James Wight and how he learnt his trade in Scotland. This series drew on archives and exclusive access to the diaries and case notes he kept during his student days in Glasgow, as well as the biography written by his son. The book to accompany the BBC series, Young Herriot, was written by the historian and author John Lewis-Stempel. The first episode was shown on BBC1 on 18 December 2011.
In September 2010, the Gala Theatre in Durham presented the world premier professional stage adaptation of All Creatures Great & Small.