The Circle Series, formerly known as the Circle Trilogy until the novel Green was released in September 2009, is a set of spiritually inspired novels by Ted Dekker, written mostly in 2004, about a man named Thomas Hunter who, after a head injury, wakes up in an alternate reality every time he goes to sleep. The stakes are raised when he realizes that a deadly virus is about to be unleashed on our world, and that the other earth is also being threatened with catastrophe.