Question: How many novels has the author of A Death in Vienna written?
Context: Daniel Silva (born 1960) is a best-selling American author of 19 thriller and espionage novels. Maureen Crane Wartski (born Maureen Ann Crane, January 25, 1940 – January 14, 2014) was a naturalized American author She wrote many novels for children and young adults.  Wartski's Eurasian heritage and her deep connection to the natural world inspired many of her novels which address such issues as racism ("The Face in My Mirror", "Candle in the Wind", "A Boat to Nowhere"), identity ("My Brother Is Special", "The Lake Is on Fire", "The Promise") and bullying ("Yuri's Brush with Magic"). The utopia and its derivative, the dystopia, are genres literature that explore social and political structures.  Utopian fiction portrays a setting that agrees with the author's ethos, having various attributes of another reality intended to appeal to readers.  Dystopian (or dystopic) fiction (sometimes combined with, but distinct from apocalyptic literature) is the opposite: the portrayal of a setting that completely disagrees with the author's ethos.  Many novels combine both, often as a metaphor for the different directions humanity can take, depending on its choices, ending up with one of two possible futures.  Both utopias and dystopias are commonly found in science fiction and other speculative fiction genres, and arguably are by definition a type of speculative fiction. Published in 2004, A Death in Vienna is a spy novel by Daniel Silva. Roy C. Booth (born August 26, 1965) is a United States speculative fiction, fantasy and horror author.  He has written many novels and short stories, many of them co-written with others including "Theater of the Macabre", "The Flesh of Fallen Angels: A Horror Western Novella" (part of the Gibson Blount series co-written with R. Thomas Riley) and "Sherlock Holmes And the Case of the Man-Made Vacuum" (co-written with Nicholas Johnson).  Booth has a credit on IMDb for "The Day Lufberry Won It All".  and a credit with Doollee, the Playwrights database. Ryan () (15 June 2000) as a famous football player and as a famous basketball player .  he was one of the best in the world.  He is one of the famous Taiwanese Poet. Taiwanese author and literary critic.  He is the author of many novels, two of which, "Wild Child" (野孩子) and "My Kid Sister" (我妹妹), were published together in the U.S. as "Wild Kids". Eve Unsell (1887 – July 6, 1937) was an American screenwriter.  She wrote for 96 films between 1914 and 1933.  She was born in Chicago, Illinois, and died in Hollywood, California.  Eve was an American scenarist who was known to also use the pseudonym Oliver W. Geoffreys as well as E.M. Unsell.  She was born in Chicago, Illinois, and died on July 6, 1937.  There is little documentation of her private life except that she was married in 1911 until her death, to a man named Lester Blankfield.  Eve Unsell was a professional in her career as a scenarist, overcoming many challenges along the way.  Eve wrote for over 96 films in her lifetime, and edited over ten.  Some of her most famous screen writes turned into productions include "Shadows" (1922), "The Ancient Mariner" (1925), "The Plastic Age" (1925), and "The Spirit of Youth" (1929).  Although she was most famous for her work in scenario writing she can also be given credit as an adapter, company director, editor, play reader, screenwriter, theatre actress, and writer.  She helped in the writing of many novels as long as editing many different pieces from literature to theatrical writing. Ottwell Binns (1872 - 1935) was a British novelist and minister (non-conforming, not of the Church of England).  Binns was a prolific author, publishing many novels of adventure and mystery, from 1917 to 1939.  His publisher in Britain was Ward Lock.  Though he died in 1935, Ward Lock continued to publish novels under his name until 1939.  His novel "A Mating in the Wild" was published in the U.S. in 1920 by Alfred A. Knopf and the A.L. Burt Company. Walter Sorrells is an award-winning author of mystery and suspense novels for adults and teens.  He has written many novels, including "Fake I.D.", named one of the ten Best Mysteries by Booklist magazine in 2005 and several novels based-on the television series Flight 29 Down.  He also writes under the pseudonyms Lynn Abercrombie and Ruth Birmingham.  He graduated from Haverford College in 1985, where he majored in History. Jon Guenther is an American software engineer and the author of nearly forty novels in a variety of genres and under multiple pseudonyms.  In addition to books under his own name, he has written many novels in "The Executioner" series created by Don Pendleton about the fictional character Mack Bolan.  He is also creator of the Christian Pulp brand and genre.
Answer: 19