Have Dean Koontz and Bernhard Schlink both written at least one novel?
yes
Title: Dean Koontz
Passage: 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".
Title: Dean Koontz's Frankenstein
Passage: Dean Koontz's Frankenstein is the collective title of five novels co-written by Dean Koontz.  Though technically of the mystery or thriller genres, the novels also feature the trappings of horror, fantasy, and science fiction.
Title: Prodigal Son (novel)
Passage: Prodigal Son is a novel by the best-selling author Dean Koontz, released in 2005.  The book is the first book released by Koontz in a series of five, entitled "Dean Koontz's Frankenstein".  The book was co-authored by Kevin J. Anderson.
Title: Phantoms (film)
Passage: Phantoms is a 1998 American science fiction horror film adapted from Dean Koontz's 1983 novel "Phantom".  Directed by Joe Chappelle with a screenplay by Koontz, the film stars Peter O'Toole, Rose McGowan, Joanna Going, Liev Schreiber, Ben Affleck, Nicky Katt, and Clifton Powell.  The film takes place in the peaceful town of Snowfield, Colorado, where something evil has wiped out the community.  It is up to a group of people to stop it or at least get out of Snowfield alive.
Title: Farhad Mann
Passage: Farhad Mann is a Canadian-American director, and screenwriter of film, television and commercials.  He directed the feature film, "Fighting for Freedom", starring Kristanna Loken, Jose Maria Yazpik, Patricia De Leon, and Academy Award nominee and Emmy nominee, Bruce Dern.  He also wrote and directed "" (1996) for New Line Cinema and his pilot "Max Headroom" (1987) ABC won several Emmy's.  He directed the critically acclaimed TV movie adaption of Dean Koontz's best-selling novel, The Face of Fear, the Dean Koontz best-selling novel.  The next pilot he directed, "Nick Knight", which became the long-running "Forever Knight", was picked up by CBS.
Title: Sole Survivor (2000 film)
Passage: Sole Survivor also known as Dean Koontz's Sole Survivor is a Canadian science fiction Thriller film/mini-series adaptation of Dean Koontz's novel of the same name, made and released in 2000 and directed by Mikael Salomon.
Title: City of Night (Koontz and Gorman novel)
Passage: City of Night is a novel released in 2005 by the best-selling author Dean Koontz and Ed Gorman.  The book is the second in Koontz's series, entitled "Dean Koontz's Frankenstein".  The third book in the series, "Dead and Alive", was published in 2009.
Title: Dead and Alive (Koontz novel)
Passage: Dead and Alive is the third novel in the first trilogy of "Dean Koontz's Frankenstein" series.  Originally intended to be co-authored by Ed Gorman and Dean Koontz, Koontz opted to write this entry alone.
Title: Bernhard Schlink
Passage: Bernhard Schlink (born 6 July 1944 in Bielefeld) is a German lawyer and writer.  His novel "The Reader", first published in 1995, became an international bestseller.
Title: Odd Thomas (novel)
Passage: Odd Thomas is a thriller novel by American writer Dean Koontz, published in 2003.  The novel derives its title from the protagonist, a twenty-year-old short-order cook named Odd Thomas.  The book, which was well received and lauded by critics, went on to become a New York Times Bestseller.  Following the success of the novel, six sequels, "Forever Odd" (2005), "Brother Odd" (2006), "Odd Hours" (2008), "Odd Apocalypse" (2012), and "Deeply Odd" (2013), were also written by Koontz.  The final novel in the series "Saint Odd" (2015) was released on Jan 13, 2015.  Three graphic-novel prequels, "In Odd We Trust", "Odd Is On Our Side" and "House of Odd" have also been released.  In the postscript to the graphic novel, Koontz states that "God willing, there will be six Odd Thomas novels."  A Special Odd Thomas Adventure (short novel), "Odd Interlude", was released on December 26, 2012.
Dean Koontz Bernhard Schlink