Dennis Koller is the author of The Oath; thriller The Custer Conspiracy; and recently published The Rhythm of Evil. He came late to mystery novel writing, spending the first 20 years of his career life in marketing. In those years, his creative urges were assuaged by writing articles for trade journals, and by writing direct response appeal letters for non-profits, mostly in the higher education space in northern California.
His company, Pen Communication, specialized in hand-written direct response pieces used by many PBS stations around the country to raise funds. It now publishes his novels. He lives in the Dallas area with his wife, Sarah.