Have Dean Koontz and Bernhard Schlink both written at least one novel?
Dean Koontz Dean Ray Koontz (born July 9, 1945) is an American author. His novels are broadly described as suspense thrillers, but also frequently incorporate elements of horror, fantasy, science fiction, mystery, and satire. Many of his books have appeared on "The New York Times" Bestseller List, with 14 hardcovers and 14 paperbacks reaching the number-one position. Koontz wrote under a number of pen names earlier in his career, including "David Axton", "Leigh Nichols", and "Brian Coffey".
Katherine Kurtz Katherine Irene Kurtz is an American fantasy writer, known for her sixteen historical fantasy novels in the "Deryni" series. She also wrote several occult alternate history novels in her "Templar" series, and urban fantasy novels in her "Adept" series.