Helen Clark MacInnes was born on October 7, 1907, in Glasgow, Scotland, where she was also educated. She married Gilbert Highet, a Greek and Latin scholar, in 1932. To finance trips abroad they collaborated in translating books into English from German. The couple moved to the United States in 1937. After her son was born, MacInnes began writing her first novel. Above Suspicion (1941) not only was an immediate best seller but also was made into a popular film, as were Assignment in Brittany (1942), The Venetian Affair (1963), and The Salzburg Connection (1968). The film Assignment in Brittany was used to help train intelligence operatives during World War II.
During the course of her life, MacInnes wrote more than twenty novels and a play. Her novels were highly successful, and more than 23 million copies of her books have been sold in the United States alone. They have been translated into twenty-two languages including Portuguese, Greek, Arabic, Tamil, Hindi, and Urdu. Her work is admired by both the general audience and professional intelligence agents. Allen Dulles, former head of the Central Intelligence Agency, called MacInnes a “natural master of the thriller” and included an excerpt from Assignment in Brittany in an anthology of espionage literature that he compiled. Not all of her novels, however, concerned espionage in foreign lands. Friends and Lovers (1947) was a semiautobiographical love story set at Oxford University in England, and Rest and Be Thankful (1949) satirized the New York literary and critical establishment, showing some of its members trying to survive at a dude ranch in Wyoming.
In 1985, MacInnes died in Manhattan following a stroke. Her death occurred shortly after her last novel, Ride a Pale Horse (1984), appeared on The New York Times paperback best-seller list.