The No 1 Ladies’ Detective Agency writer, 69, said the new books would not fit the gritty Scandi noir genre, however. Instead, they may form a new category he calls “Scandinavian blanc”.
The first book in the series, which has already been completed, will be called The Department of Sensitive Crimes.
The book, due to be published in the UK and US next spring, will introduce his loyal readers to detective Ulf Varg and his hearing-impaired dog Marten.
Their first mysteries will include an apparent case of lycanthropy – the mythical transformation of a person in to a werewolf.
The author said: “I’ve started a new series set in Sweden. I call it ‘Scandi blanc’ as opposed to Scandi noir.
“My central character is a Swedish detective called Ulf Varg – Ulf means ‘wolf’ in Danish and Varg means ‘wolf’ in Swedish so he’s Wolf Wolf.
“He lives in Malmo and works in this department which deals with unusual crimes.
“He has a dog called Marten, and he’s hearing impaired. He’s the only dog in Sweden who can lip-read, but only in Swedish.
“He also has various sidekicks, but all his cases are really peculiar.
“The whole thing is just having great fun. My books never involve any serious crimes. Nobody is ever killed in any of my books, so there’s no murder there.
“There is a case of lycanthropy, though – somebody who is possibly a werewolf. It’s good Scandinavian stuff and I’ve had tremendous fun.
“I’ve written the first novel, which will be published in London and New York, as my American publishers are very keen on it, and I can’t wait to write volume two.”
He added: “Sweden is one of the countries where my books are particularly sold.
“But I’ve not written it with my Swedish readers in mind – I think they may be entirely puzzled by these books.”
McCall Smith is prolific, putting to paper 1,000 words per hour and completing “four or five books a year”.
He said: “It breaks all known rules of publishing, but I enjoy it. If I didn’t enjoy it I wouldn’t do it, so I have various series that I keep going and there is a particular season of the year in which I do each of them.
“I don’t really stop to think about it very much. I sometimes use the analogy of walking on a tightrope – not that I have ever done so – but I imagine you don’t look down, you just carry on walking.
“I’m in the happy position of being able to write quickly.”
McCall Smith is celebrating the twentieth anniversary of his hugely successful No 1. Ladies’ Detective Agency books, set in Botswana.
The author is currently completing his 19th book of the series, and admitted the books – and main character Precious Ramotswe – could go on as long as he does.
He said: “I’ve certainly got no plans to bring the career of Precious Ramotswe to an end because I very much enjoy my annual conversation with her.
“As long as I am spared I am going to continue to do that.
“Obviously they are going to come to an end at some point but that depends on other factors.”