In British TV personality Osman’s The Thursday Murder Club (Viking/Dorman, Sept.), four retirement home residents fascinated by crime attempt to solve a murder.

Where did the idea for the novel come from?

I have a good friend whose mum lives in a retirement village, and we went to visit her. It was so calm and peaceful, miles from anywhere, no mobile phone reception, just heaven. I’m not sure what it says about me, but, as I sat there, drinking a G&T in the sunshine, my first thought was, “Well, this would be a perfect place for a murder.” A little later we were having lunch, and I found myself surrounded by this incredible group of people. Almost all over 70, almost all laughing and joking with friends, and almost all with a drink in their hand. I chatted to a few people, heard a few stories, and realized the extraordinary range of skills on display. And then I had the thought, “Well, if there was a murder here, you can be pretty sure that this lot would solve it.” I started writing the next day.

What appealed to you about having your sleuths be elderly?

Having four characters in their 70s was an absolute joy from the very start. The idea that we underestimate older people is the key to the book. The joy of writing it was that my four detectives might look gentle and harmless on the outside, but they are far from that on the inside. And, as people will read in the book, all four of them are overlooked and underestimated throughout—by suspects, by cops, by everyone. They use this to their advantage in a number of ingenious ways.

In what way has your work on quiz shows influenced your writing fiction?

People will read maybe 30 pages of a new book before making their mind up. They’ll probably watch about 30 seconds of a new TV show before switching over to Grey’s Anatomy reruns. So in a TV quiz, you grab people quickly, you explain the rules quickly, you give viewers a reason to stay to the end, and then you give them a host and contestants who they want to spend a bit of time with. I suppose that’s how I went about writing. Grab them, and then entertain them, and then give the answer they were looking for. I worry that if I started described the color of the sky for a page and a half, people would put the book down and watch Judge Judy instead.