Dr. Stephen Falken is a brilliant computer scientist who is responsible for creating and developing artificial intelligence in computers which allow them to learn from their experiences. His greatest achievement was a computer system called "Joshua", which was created for and used by the American military.
Falken's work with the assistance of John McKittrick led to the creation of WOPR, a machine intended to continuously simulate a series of "War Games" in order to predict and calculate an estimation of a possible World War III outcome.
He had a son named "Joshua" and a wife, whom both were killed in an unfortunate car crash. Shortly after his son and wife's death, he came up with the computer program with the same name that ran on WOPR. It's strongly suggested that this accident is what drove Falken to denounce his government work and request a quiet "death" from the United States Department of Defense, for whom he worked for many years.
His alleged "death" was arranged by the United States military at the time he was 41 due to security concerns, right after he had "given up" on the humanity. He had been living the of his life under the alias Dr. Robert Hume, on Goose Island, Oregon 97 with a new found archeology/history hobby, right until he met David and Jennifer who were successful to change his mind.