Marion Chesney, who in midlife began writing novels and produced more than 150, including mystery series written under the pseudonym M.C. Beaton that featured the endearing crime solvers Agatha Raisin and Hamish Macbeth, died on Dec. 31 at a hospital in Gloucester, in western England. She was 83.

The St. Martin’s Publishing Group, whose Minotaur Books published her Agatha Raisin series, announced the death. No cause was given.

Ms. Chesney held an assortment of jobs, including several in journalism, before publishing her first novel in 1978. She wrote romances before turning to mysteries in 1985 with “Death of a Gossip,” the first of more than 30 Hamish Macbeth stories.

A later novel described Hamish, the constable in the fictional village of Lochdubh in the Scottish Highlands, as “tall and gangly and lanky and unambitious,” yet he had a shrewdness that, book after book, enabled him to crack cases. A BBC television series based on the books, with Robert Carlyle as the constable, ran in Britain from 1995 to 1997.