When I first proposed the Daisy Dalrymple mystery series to my agent, I'd chosen my period (1920s), my setting (England), and my protagonist (Daisy). I had decided Daisy would be of an aristocratic family, so she could question a duke about why he was in the library at the stroke of midnight, but impoverished, so she had to work for a living. And I made her a journalist to give her an excuse for finding bodies all over the country, thus avoiding St. Mary's Mead/Cabot Cove syndrome.
In Heirs of the Body (just out in paperback), for instance, she's staying at her family's estate in Worcestershire.
Beyond that, all I knew was that I didn't want to have to think up titles. I had already written over 20 Regencies and I was tired of coming up with good, eye-catching, memorable titles. I decided my series would be Death in January, Death in February, Death in March, etc. Each plot would be related to the month. Thus the first would have a body in a frozen lake.
Well, St. Martin's Minotaur, who bought the story, had recently done an anthology based on months. They nixed my series titles, hence the utterly unmemorable Death at Wentwater Court (just reissued 20 years later).
It turned out lucky that the "death of the month" idea was killed, so to speak, as the series might otherwise have died after 12 books. There are now 22, with a 23rd contracted for.
What has kept the series going for so long? Judging by what I hear from readers, the main factor is Daisy herself. She's a friendly person. People come to think of her as a friend and want to spend more time with her. They want to find out what happens next, not only as regards her adventures in detection but in her life.
Second in importance is balancing change with the kind of predictability readers want in a series. I couldn't—and wouldn't want to—introduce graphic blood and guts, for instance, or a mad serial killer, or "mean streets." That's not what people are looking for in this kind of series, whether you call it cozy or traditional.
What changes is the setting, most of the characters (besides Daisy and Alec, some reappear in most or a few of the books), and the where, what, when, how, and why of the murder, and its outcome. Thus every story is familiar yet fresh.
The 22nd in the series, Superfluous Women, has just come out.
The review in Library Journal says:
"The 22nd entry...proves that Dunn just keeps getting better."
Can't beat that!
Carola Dunn is the author of 22 Daisy Dalrymple mysteries and 3 Cornish mysteries, all published by St Martins Minotaur. She has also written 32 Regencies, now out of print but available as ebooks. Born and raised in England, she has lived in the US for more decades than she cares to count, presently in Oregon. She loves reading, gardening, classical music, and walking by the Willamette with her rescue dog, Trillian.
You can find Carola on Facebook (personal and 4 author pages) as well as her website, www.CarolaDunn.weebly.com. She also blogs regularly on www.BloodRedPencil.blogspot.com. She enjoys hearing from readers.