While trying to keep the shop going, Marsh filled in odd moments in writing her first book, a detective novel called A Man Lay Dead. Details of its composition and the invention of Inspector Roderick Alleyn are given in Marsh’s essay, “Roderick Alleyn,” which begins this book. Shortly after finishing the manuscript, she had to return to New Zealand to attend her mother’s ultimately fatal illness, but her English agent arranged for the book to be published in 1934. In later years, Marsh grew disenchanted with A Man Lay Dead. In her autobiography, Black Beech and Honeydew, she remarked that “I don’t think that before or since… I have ever written with less trouble and certainly with less distinction.”

“It wasn’t very good,” she said to an interviewer, “and sometimes [I] wish it could be withdrawn. I don’t like the title even. It sounds awfully like ‘A Man-Laid Egg.’ ” To modern readers Alleyn seems something of a twit on his first appearance, as is evident from his very first words: “You’ve guessed my boyish secret. I’ve been given a murder to solve—aren’t I a lucky little detective?” And the solution—involving the murderer sliding down a bannister toward the victim—does not have the subtlety of her later books. Enter a Murderer (1935), written in New Zealand while Marsh was keeping house for her father, was a marked improvement, perhaps because it was based on her first love, the theater, but Alleyn still talks like one of the “bright young things” of the 1920s. His first words in this book are: “Perhaps he knew me. I’m as famous as anything, you know… An actor in his dressing-room will thrill me to mincement. I shall sit and goggle at him, I promise you.” Though in each successive book Marsh gradually deepened his character, Alleyn does not become truly believable until he meets his future wife, the painter Agatha Troy, in Artists in Crime (1938).