It is a simple matter of observation and deduction, the one informing the other. Were I to explain it to you, it would all seem painfully childish.

It is November 1890 and London is gripped by a merciless winter. Sherlock Holmes and Dr Watson are enjoying tea by the fire when an agitated gentleman arrives unannounced at 221b Baker Street. He begs Holmes for help, telling the unnerving story of a scar-faced man with piercing eyes who has stalked him in recent weeks.

Intrigued, Holmes and Watson find themselves swiftly drawn into a series of puzzling and sinister events, stretching from the gas-lit streets of London to the teeming criminal underworld of Boston and the mysterious ‘House of Silk’ …

How do I set about creating a murder mystery? This is another question that often comes up at literary festivals. For me, all murder stories boil down to a very simple formula: A+B=C. A is one person. B is another person. C is the reason why A wants to murder B. The genius of Agatha Christie was that she managed to find so many variations on this basic formula. The narrator did it. The detective did it. The little boy did it. They all did it. And yet, the strange thing is that when you come to think them up, there are very, very few reasons why anybody actually wants to murder anybody. In fact I can only really think of three: money, fear and passion … which may be sexual passion, revenge or whatever.I see a murder story as a series of concentric circles, almost like a dart board. At the very centre is that equation. It is where I start because it is both the beginning and the end; the springboard and the solution to the crime. But then I have to add the next levels. The other suspects. More stories which, though often irrelevant, nonetheless link up with the bull’s eye. In Foyle’s War, I would add whole stories which had nothing whatsoever to do with the crime but which in many ways interested me much more: anti-Semitism in Britain, the birth of plastic surgery, funk holes, spies, etc These would all be layered in. Every book has to have a shape. A murder story is circular.

I think I liked more the author’s notes on how he created the novel rather than the actual Sherlok Holmes story. It was an interesting read and while the usual suspects were afoot, the reveal and the twists and turns made it into a very good detective novel.

Taken off one star due to the fact the author is recycling characters another person wrote, much like Rick and Morty – the Anime. At least he did a good job with it.