The book is set in an alternate 19th-century Britain, during the Napoleonic Wars. The story is based on the premise of magic returning to England after hundreds of years of desuetude, and the tumultuous relationship between two magicians of the time. It incorporates historical events and people into its fictional alternate reality. Historical figures encountered in the novel include the Duke of Wellington, Lord Byron and King George III. The novel, written in a pastiche of Jane Austen and Charles Dickens' literary styles, uses quasi-archaic spelling for several words (such as shew, chuse, sopha, scissars, headach, and surprize) and gives all street names hyphenated with only one capital letter (e.g. Regent-street, Hanover-square).
The book is interspersed with footnotes which reference a number of fictional books including magical scholarship and biographies, and which provide a detailed backstory. Many pages of the book contain more footnote text than main body text. The book features several illustrations by Portia Rosenberg.
In addition to the historical personages, the reader is introduced to many characters, including:
At one point in the book, reference is made to the Faerie kingdom of Pity-Me. This is in fact a real place in County Durham, North East England. Clarke was living in County Durham in 1992, when she started writing the novel.
In the book the King, afflicted with madness, is in the care of a pair of doctors called the "Willises." These characters are based on George III's actual physician Dr. Francis Willis. However the portrayal of his treatment and his relationship with the doctor(s) are closer to how they are characterized in the play The Madness of King George than they are to the actual events.
Historical figures encountered in the book, either directly or in passing, include:
The book received favourable reviews from critics. The review aggregator Metacritic reported the book had an average score of 83 out of 100, based on 25 reviews (which puts it in the category "Critical Acclaim"). The novel is also a New York Times and Sunday Times bestseller. Time Magazine named it the best novel of 2004.
Critical acclaim from fellow authors includes Neil Gaiman, who said the book was "unquestionably the finest English novel of the fantastic written in the last seventy years", and Charles Palliser, author of the similarly grand-scale, Victorian-set The Quincunx, who praised the book's depth of invented background; "I almost began to believe that there really was a tradition of 'English magic' that I had not heard about."
Christopher Hampton was purportedly adapting the book as a motion picture for New Line Cinema. Clarke has partnered with newly formed Cuba Pictures to produce the film. A December 6th 2007 interview, however, with Hampton quotes him in response to the question, "I’ve heard a rumor that you’re doing the adaptation of "Jonathan Strange and Mr. Norrell" as saying: "I’m not doing that anymore. I started out on that, but I slightly fell out with them on the topic that I often fall out with, which is that they seemed to want to go too far away from the book for my tastes." (http://www.filmhobbit.com/new/Interview-Christopher-Hampton-Of-Atonement-7115.html)
History and Practice of Magic by Paul Christian, which was first published in 1881 and has been reprinted numerous times, appears to be one of Clarke's sources on magic. The original edition included detailed accounts of folk beliefs about mystery schools and initiatory rites, discussing ceremonial magic and witchcraft, as well as divination through astrology and tarot (and esoteric beliefs about same). Clarke also seems to have used Eliphas Levi's History of Magic, another 19th century work, originally published in French.
The book's cover features a blurb by Neil Gaiman, who is also responsible for Clarke's first publication - he introduced Patrick Nielsen Hayden to a short story set in the same universe, which was subsequently included in the anthology Starlight 1.
Certain parallels may also be drawn with speculative fiction authors such as Michael Moorcock and Jack Vance. Like her, these authors have played with the conventions of 19th and early 20th century culture. (A minor character called Moorcock actually appears in Clarke's book as Sir Walter Pole's secretary.)