Helen Reilly was born in New York City in 1891. Her father was John Michael Kieran, the president of Hunter College, and her brother, John Kieran, produced the famous Information Please series, a radio program that showcased his encyclopedic learning. Helen married Paul Reilly, an artist and cartoonist, in 1914, before she completed her degree from Hunter. The couple had four daughters, two of whom, Ursula Curtiss and Mary McMullen, followed in their mother’s footsteps as mystery writers. (Her brother also wrote a mystery.)
At the urging of her lifelong friend, William McFee, an eminent author, Reilly began writing detective stories. Almost all of her stories feature Inspector McKee and follow the formula of a detailed presentation of a homicide investigation, told from the point of view of the police. It is easy to understand Reilly’s reason for writing this way—her stories were major successes. She wrote thirty-three mysteries in her thirty-year career, as well as three others under the pen name Kieran Abbey. The leading magazines of the time that published popular fiction, such as The Saturday Evening Post and Collier’s, often featured her work. She served as president of the Mystery Writers of America in 1953.
She lived in Connecticut for a number of years; this state is the setting of Certain Sleep (1961). After her husband died in 1944, she returned to New York. Although she eventually moved from New York City to Santa Fe, New Mexico, to live with her daughter Ursula Curtiss and the latter’s family, she always considered herself a native New Yorker. She died on January 11, 1962, continuing to write almost to the end of her life.