Monahan wrote a novel titled Light House: A Trifle, and Warner Bros. optioned the film rights. In 1999 Talk magazine debuted, and Monahan contributed a travelogue on Gloucester, Massachusetts, to the first issue. In 2000 Monahan's first novel, Light House: A Trifle, was finally published, and it garnered critical acclaim; The New York Times proclaimed, "Monahan's cocksure prose gallops along" and BookPage Fiction called Monahan "a worthy successor to Kingsley Amis." In the second half of 2001 Monahan wrote a fictional column at the New York Press under the pseudonym of Claude La Badarian, which ran for 13 weeks.