Robert Louis Stevenson was a remarkable man. Not only did he produce some wonderful books but he was allowed a degree of freedom few of us can enjoy today. Stevenson wrote a children’s adventure classic Treasure Island and the dark gothic horror of Dr Jekyll and Mr Hyde. He penned the historical novel Kidnapped and The Master of Ballantrae, a kind of international revenge blockbuster with locations ranging from the Scotland of the Jacobite Rising to America and India. There was plenty of journalism and travel too, all in a mere forty four years of a life blighted by sickness.

No one ever said to Stevenson, ‘Stick to what you know, dear boy.You can be a kids’ writer, a teller of adventure tales, a master of horror, or the forerunner of the Clavells and Archers of the century to come. But you can’t be them all.’

He was lucky. Very few authors will find themselves so fortunate today. We live in the era of genre, of intense and rigid classification. In the 1960s, when I was a teenager browsing the shelves of the library in the small town where I grew up, already imagining where a book bearing my name would end up on the shelf, titles were divided into the most basic of categories.

One part of the library was for fiction, one for non-fiction. The only sub-division in fiction might be an area where the sci-fi titles were kept, usually in the tell-tale yellow jackets of Gollancz. Everything else – from Mary Renault to Henry James, from Raymond Chandler to Somerset Maugham – was arranged alphabetically on the same shelves.

I grew up reading books of all kinds, not a set selection relegated to a genre, a pre-defined classification of the rich and sprawling world of literature that someone had kindly sifted and sorted beforehand. Like Stevenson. I was lucky too.

Today most popular fiction comes with a label attached. Crime, young adult, thriller, mystery, history, chick-lit, science fiction, fantasy, romance, romantasy… These interbreed so we also have chick-lit mysteries and historical crime. Then there are the sub-genres such as noir, steampunk, gothic, hardboiled, legal, police-procedural, speculative and alternative history.

Some of these terms have geographical limitations. American readers are always surprised to learn that the word ‘mystery’ means precious little to their counterparts in the UK. The US term ‘cozy’ – used for a crime novel that avoids nastiness such as overt violence, sex and bad language while still managing to kill people somewhere along the way – used to be equally foreign to most readers outside America, though the kind of book it describes is universally popular. But both are gaining currency in the UK now too.

Rail against the rise of the genres as much as you like, but you would be foolish to ignore it. One way or another your book will probably be defined as belonging to one of these categories, even if only tentatively. Accept that fact and start to understand how best to use it. You’ll stand a much better chance selling your work as ‘upmarket crime’ than as ‘general fiction that happens to involve a murder’.