Todd Ritter, known by his pseudonyms Riley Sager and Alan Finn, is a New York Times bestselling American author known for his thriller novels. His writing career took off with his first thriller, "Final Girls", which won the ITW Thriller Award for Best Hardcover Novel. This novel has been published in over thirty-five countries, showcasing his international acclaim.

Riley Sager has authored eight novels, including the notable titles "The Only One Left" and "The House Across the Lake". As of June, his latest novel, "Middle of the Night", will be released.

A native of Pennsylvania, Sager now resides in Princeton, New Jersey. Outside of writing, he enjoys reading, cooking, and watching movies. Among his favorite films are "Rear Window", "Jaws", and "Mary Poppins".