Robert Finnegan was born Paul William Ryan on July 7, 1906 in San Francisco, California. He worked at many jobs in his lifetime including that of sailor, bookstore worker, Longshoreman's Union writer, director of public relations for the WPA Writer's Project, broadcast producer for the National Maritime Union as well as a reporter for a west coast daily. Ryan was active in the Communist Party, and many of his books were published by the party's publishing house under the name Mike Quin. As Finnegan, he wrote three hardboiled novels in the 1940s featuring detective Dan Banion. He died from cancer on August 14, 1947 in Olema, California.