* David Powers: A well-known American author who has written numerous books, including "The Last Days of John Lennon" and "The President's Man."
* Guy Gavriel Kay: A Canadian author known for his historical fantasy novels, such as "Tigana" and "A Song for Arbonne."
* David Power: A British author of thriller novels.
It is possible there is an author named "David Guy Powers" but he is not very well-known or his works are not widely available. Could you please provide more information about the author or his work?