Cynthia Cidre (born July 10, 1957) is a television writer best known as the creator of and writer for the long-running TNT series Dallas .Cynthia was the creator and an executive producer for the CBS prime time soap opera Cane in 2007 and wrote the scripts for the films, In Country (1989), A Killing in a Small Town (1990) and The Mambo Kings (1992). In 2015, she joined as co-showrunner another prime time soap opera, Blood & Oil on ABC.