With Holmes the reader is not wearied by the author’s concerns to meditate on the ills of society or present his insight into character, both of which would have made the stories date far more obviously. Nor does he have those tastes and interests – cooking, cultivating orchids, body-building, or whatever – which are often grafted on to characters to give them an appearance of depth. He plays the violin and used to box; that is almost all we know about him and these are referred to rarely and economically. Even his habit of using cocaine is referred to in passing only: it is not used as a way of excavating his character. Holmes’s personality is so strong because he is supposed not to have one; he is meant to be ‘cold, precise, but admirably balanced… the most perfect reasoning and observing machine’ (‘A Scandal in Bohemia’). Seen through the eyes of Dr Watson – the perfect embodiment of open-minded yet conventional Victorian society – this gives him his unique and fascinating eccentricity.

In other words, however, Holmes’s popularity endures despite what is in the stories, through an almost deliberate attempt to ignore some of the implications of the tales. For the character presented is the archetypal ‘new man’ of the Victorian age, a meritocrat, living solely off his brains, dislocated socially and scornful of the society in which he lives. This is, again, in complete contrast to later varieties of English detective; Holmes doesn’t really care about society, seeing it mainly as a producer of intellectual puzzles – ‘the status of my client,’ he says in ‘The Noble Bachelor’, ‘is a matter of less moment to me than the interest of his case’. Most of the aristocrats who walk through the pages are presented in a less than sympathetic fashion and, while there are hints that he is a patriotic Englishman, properly loyal to the throne, there are none that this patriotism extends to any great affection for the English class system. The heroes of later years, in contrast, are all very conservative figures, from the snobbish Poirot to the aristocratic Wimsey, Campion and Alleyn. Holmes is instead uprooted from his place in society, indeed has uprooted himself – we learn through hints that he comes from the squirearchy, but no more; his background is of no importance in comparison to his own intellectual merit. Holmes is, purely and simply, his method and the cases he solves; it is perhaps significant that much of the Holmes industry which now exists occupies itself in seeking out those details – through guesswork, cross-referencing and so on – which Conan Doyle deliberately omitted.

Dr Watson, in contrast, is by far a more fleshed-out character; we are given more hard facts about his life than about the hero of the stories, and the division which gives most of the action to one figure, and most of the character development to the other, is a strange literary device which proves remarkably effective in practice. Had the stories depended on Holmes alone, they would perhaps have been a little too dry; had Conan Doyle tried to fill out Holmes’s character, he would have diminished the mystery: Holmes is fascinating because nobody really knows him well. Instead, Conan Doyle adopted the risky technique of all but forcing the reader to identify with the second string, the man constantly shown up by his friend’s brilliance, whose instincts and conclusions are an infallible guide only to what did not happen. Many successors tried this technique, but few succeeded; certainly, no one ever created a secondary character who himself stands as a major creation.

For Watson is a considerable invention and, despite his obtuseness, is an admirable man possessed of all the human virtues except great intelligence. He is courageous, loyal, capable of human relationships quite beyond Holmes’s range and, above all, he is a man of the greatest tolerance. He puts up with Holmes (no easy matter) as well as with various acquaintances who are cocaine addicts or other reprobates normally excluded from society by right-thinking men. Not once in all the stories does a moral judgement slip from his pen, even when dealing with high-class prostitutes in ‘A Scandal in Bohemia’, interracial marriages (‘The Yellow Face’) or bigamists (‘The Noble Bachelor’). Aristocrats and their mistresses excite Holmes’s contempt, but Watson passes no comment. Again the contrast with stories from the ‘golden age’ of crime writing, the interwar years, is striking – only Agatha Christie shows any of Conan Doyle’s tolerance, while racist, anti-Semitic and morally judgemental comments flow freely from the pens of far too many others. Through Watson, we have a picture of at least one section of respectable Victorian society which was far more easy-going and tolerant than anything that emerged for several decades afterwards. He stands as a character who is a worthy foil to his more famous associate because of these understated qualities. He is a decent, honest man who manages not to be dull by virtue of his openness to new experiences and his utter lack of pretension: it is hard to dislike a narrator who so freely illustrates his friend’s brilliance by contrasting it with his own lack of perception; that Conan Doyle manages this without Watson ever seeming disingenuous, dull or false in his modesty is a measure of his skill.

Rather than the lands of aristocrats, squires and the wealthy, Holmes’s primary stamping ground is the parts of Victorian London untouched even by the likes of Dickens, and many of his subjects are the residues of Empire washed back to the Mother Country. In addition to the East End and the docks, he also operates in the ‘near country’, the new suburbs which grew up around the city in the nineteenth century, like Norbury, Lee, Pinner – all areas later ridiculed into obscurity for their lower middle class respectability but which then had not yet acquired their reputation for bland dullness. The further out into suburbia he goes, the weaker Conan Doyle’s descriptive powers become, although in all fairness it must be said that scene-setting was not a high priority for him. None the less the deft touches which set out the locale in, for example, ‘The Red-Headed League’ or ‘The Man with the Twisted Lip’, rather elude Holmes when he gets as far as Dartmoor in ‘Silver Blaze’; only in longer stories such as The Hound of the Baskervilles (1902) does he pay much attention to scenery, and even then the landscape is often conveyed through the characters who inhabit it. Indeed, far more important than physical location in the early short stories is his description of character, which is as much part of Conan Doyle’s art as it is of Holmes’s, and in a succession of thumbnail portraits he demonstrates an impressive ability to capture personality and types in a minimum of words.

Many of the characters in the stories have been abroad, principally in the Empire. Indeed, it is extraordinary how many of them have at some stage been in Australia (‘The Boscombe Valley Mystery’), America (‘The Five Orange Pips’, ‘The Noble Bachelor’, ‘The Yellow Face’), India (‘The Speckled Band’, ‘The Crooked Man’), Nova Scotia (‘The Copper Beeches’); and how many of the stories involve people who, willingly or not, have travelled widely (‘A Scandal in Bohemia’, ‘The Gloria Scott’) or are foreigners (‘The Engineer’s Thumb’, ‘The Greek Interpreter’). More remarkable still is the frequency with which the crimes narrated in the stories are generated abroad and then brought back to play out their consequences in England; much of Holmes’s work is to preserve the country from the corruption of foreign places, and that of the Empire in particular: one almost thinks that without this foreign contamination even London would be a remarkably peaceful, law-abiding place.

Aside from that, Conan Doyle specializes in the struggling middle and lower-middle classes, alone in the office waiting for customers and struggling to maintain a position – Holmes himself, as he mentions in ‘The Musgrave Ritual’, a doctor in ‘The Resident Patient’, an engineer in ‘The Engineer’s Thumb’; or in people forced to extreme measures to preserve appearances – hence the deception in ‘The Man with the Twisted Lip’. The desire to hold on to sums of money which later writers would consider almost derisory provides the motives at the heart of ‘A Case of Identity’, ‘The Speckled Band’ and ‘The Copper Beeches’, all of which are powered by questions of inheritance and give a more or less orthodox Victorian air to tales which, generally, are remarkably free of such period devices.

Distinctly in the minority in the stories, however, are criminals; even though Conan Doyle refers several times to London as being full of such people, true criminals in fact make only rare appearances.