Benedict Cumberbatch in the BBC’s modern take on the Holmes stories, Sherlock [Alamy Stock Photo]

A DEER-STALKER hat, an Inverness cape, a meers-chaum pipe and a magnifying glass – four recognisable trademarks of the original and best-known sleuth, a character who has influenced storytelling since he made his debut in Victorian times and continues to be reimagined and adapted for every generation since.

The who, how, where and why of Sherlock Holmes is the riddle author Andrew Lycett sets out to solve in his latest book, The Worlds of Sherlock Holmes.

In it the author places the world’s foremost deducer on a pedestal so we can walk round the character and enjoy a 360 degree view. We discover what lies behind that famous image, the man who created him and the world into which both were born and shaped by.

This accompaniment to the life and times of Holmes is a natural fit for Andrew. Previous works include studies of Wilkie Collins, Rudyard Kipling – and Sir Arthur Conan Doyle.

“I’ve specialised in writing biographies,” he told Review.

“Here I write about a fictional character, looking into the places he visited, the political and social background to his stories, the intellectual and scientific ideas that go into them, how they reflected contemporary ideas about detection, as well as art, sport, plus Holmes’s afterlife, including film.”

This companion embarks on a lively tour of the politics, cultural and social circumstances of Holmes’s era.

“I set out with a thesis that both Conan Doyle and Sherlock Holmes were about questing in different ways,” says Andrew. “They lived in a world expanding into new areas of the globe, which was finding out new things in fields like geology, medicine and physics in a post-Darwinian age. Holmes was questing in his speciality of detection, while Conan Doyle was on a lifelong quest, first as a doctor, and then, when he could no longer contain the itch, as a spiritualist, because he thought that explained everything.”

Andrew takes us inside Holmes’s mind, a mix of imagination to read a criminal’s intentions with a scientific approach to solving riddles.

“He flourished in the late 19th century when the spirit of rationality carried all before it,” writes Andrew.

Strides were made in all manner of scientific nooks and crannies and this expanding empiricism swept up unchartered disciplines, such as unravelling the mysteries of interior and exterior universes.

Freud was developing psycho-analysis, Planck was working on quantum theory, and Einstein was due to publish his research on a theory of relativity.

Andrew Lycett

Andrew notes that Conan Doyle was born the year Charles Darwin changed the course of history with On the Origin of Species.

“Underpinned by the insights of Enlightenment philosophers, who stressed scepticism, rationality, and empiricism, the spirit of scientific experimentation and enquiry had thoroughly permeated British society by the Victorian era,” adds Andrew.

“Holmes represented their respect for the merits of close observation, their enthusiasm for discovery, their confidence in the accumulation of knowledge, and their sense of the exciting new possibilities, both physical and intellectual.”

Andrew finds clues for Holmes’s inspirations. One suspect is the writer’s medical school tutor, Dr Joseph Bell, a professor of surgery.

Bell was known for ‘his meticulous observation of his patients, not simply looking for medical symptoms but for all sorts of personal traits,” writes Andrew. “Bell could tell from a man’s appearance and behaviour that, for example, he had recently served in a Highland regiment in Barbados.”

Clues included the patient failing to remove his hat, and the disease he had. “The Holmesian technique of investigation was based on such principles,” writes Andrew.

But Conan Doyle, who was conflated with his fictional character, did not stick to scientific rationalism.

The death of his wife Louise in 1906 of TB affected him greatly.

When war broke out in 1914, Conan Doyle’s active imagination, his thirst for discovery and the horrors being unleashed tipped him into Spiritualism.

Interestingly, this journey into hocus-pocus did not take Holmes with him: in 1924, when Conan Doyle was a signed-up believer, his detective was debunking such endeavours in The Adventure of the Sussex Vampire.

“The Detective declares… ‘This agency stands flat-footed upon the ground and there it must remain. The world is big enough for us. No ghosts need apply’.”

AF Fotografie / Alamy Stock Photo and Universal Art Archive / Alamy Stock Photo

London is a key character, Holmes and the capital are intertwined, our image today of the period partly formed by Conan Doyle’s descriptions.

He shrouded streets in fog, pale gas flames creating eerie globes of light that barely penetrated a foot from its source and made shadows appear more sinister. Holmes’s haunts reflected the cultural mores of London at play.

He dines at Simpsons in the Strand, spies on shady types in the Café Royal, hob nobs at the clubs of Pall Mall, strides across Piccadilly Circus, rushes through Covent Garden and meets people in Trafalgar Square. Further east, the Thames docks provided a seedy background for criminality.

“London’s quirky, restless energy permeates his stories,” adds Andrew.

“His adventures show off the capital in all its splendour and diversity, transporting readers from the grand mansions of Hampstead to the slums of the East End.”

Andrew recalls Watson’s earlier description of London as “that great cesspool into which all the loungers and idlers of the Empire are irresistibly drained”.

It gave Holmes the stage to perform on.

“This imperial magnet attracts a colourful range of aristocrats, scoundrels, foreigners and natives, whose exploits go to make the Holmes stories so rich and entertaining,” he says.

Holmes reflected society – and society was influenced by him.

“The Holmes stories, and their popularity from their start in the 1880s, helped teach readers to look at and think about their environment,” says Andrew.

“They entertained a generation of often recently educated people in an age before films. They are not exactly radical, so on one level they gave hope to readers who, somewhat fearful of the changes of the fast-moving technological world, wanted an element of certainty, a feeling that criminals would be brought to be justice, and all would be well. But one of the features of the Sherlock Holmes canon and one of the reasons for its continuing success is that while the detective does bring order to aspects of his world, he leaves many things up in the air. He allows several of the people he apprehends to have their freedom; he doesn’t hand them over to the authorities. He creates his own justice. Holmes is a figure for all the ages.”

• The Worlds Of Sherlock Holmes. By Andrew Lycett. Frances Lincoln, £25