By Maggie Taggart
BBC NI arts correspondent
The series of books by Edinburgh academic Alexander McCall Smith about a lady private detective in Botswana have sold in their millions.
Alexander McCall Smith returned to his old Queen's University haunts
In fact, he can't even begin to count the number translated into other languages.
The former professor of medical law has just published the eighth novel in his No. 1 Ladies Detective Agency series, entitled Miracle at Speedy Motors.
On a visit to Belfast, he told me how he has written a short story about the city, inspired by the time he spent there as a university lecturer.
It's called Animal Intelligence and is the story of a local man who returns to Belfast from London to live in the Malone Road house bequeathed to him by his aunt.
He buys a cat which he then believes is trying to kill him.
"It's a ridiculous piece of nonsense," says McCall Smith.
"When I knew I was coming to Belfast, I thought up the story to commemorate the visit.
Jill Scott will star in The No. 1 Ladies' Detective Agency
"I have very fond memories of the city and Queen's in 1973 and 1974, even though it was a bad time during the Troubles. I think it was a formative time for me."
Alexander McCall Smith's day job was as a professor of medical law in Edinburgh, but he also lectured at Queen's University's law faculty in the 1970s.
He's now better known for writing those gentle detective stories set in Botswana.
His books, featuring the unconventional No.1 Ladies Detective Agency, have sold 15 million copies in English, not counting the 42 languages they've been published in elsewhere.
"I think the best thing I can do is just stop counting," he joked after failing to tot up the number he has sold worldwide.
Belfast is the inspiration for one of his new stories
The author has also written a series of books set in his home city of Edinburgh, so could he now dream up a theme for stories set in Belfast?
"Oh, I don't think so. I think to write about a place you need to know it pretty well, so I would need to come and live in the city again," he says.
"I think it is best to leave that to all the very good local writers you have here."