Now the 50-year-old author has written his first novel, _Made in America_. Published in September by Viking, it is a raw, violent, grimly humorous story of an ex-football star for the New York Giants who gets mixed up with organized crime while borrowing money for a shady investment scheme. King Kong Karpstein, the terrifying loan shark who dominates the book, is based on several people whom Maas had known personally, and the novel's head Mafia character has much in common with Frank Costello, the "prime minister of the underworld," who granted Maas 11 interviews shortly before his death in 1975. The scenes of _Made In America_ -- porn parlors, criminal hideaways, the FBI offices -- are all described with the same intense realism as the characters. The movie rights have been sold for $450,000. "The reason I wrote it," explains Maas, sitting restlessly at his 11-room Eastside apartment on a recent afternoon, "was that I didn't want to wake up 10 years from now wondering what would have happened if I had written a novel. ... I also think a writer has to challenge himself constantly. I don't think he should play a pat hand." As he talks on in his breezy New York accent, fidgeting with a gold matchbox on the antique table beside him, Maas seems barely able to restrain himself from getting up and pacing the room. Quite striking in appearance, he is a tall, stocky man with a Brillo-pad thatch of silvery hair and eyebrows like cotton batting. A native Manhattanite, he was one of the country's top investigative reporters for many years before writing his first book, _The Rescuer_, in 1967. The reason for the title _Made In America_, says Maas is that "the events in the novel could only happen in America. ... One of the themes is that nobody in the book, including the football player and the federal prosecutor, thinks that he's doing anything wrong. So that's a very profound kind of corruption." Like his previous books, _Made in America_ took two years to write. "The biggest difference that I found," he points out, "was that in nonfiction, all the discoveries and surprises are in the research, and in fiction, they're all in the writing. When I write nonfiction, about two thirds of the time is spent in research. I didn't do any research for this. It was much harder. And it was the only time I had to rewrite the whole book." Although Maas claims that his own life has never been in imminent danger, he was touched by deep personal tragedy in 1975 when his wife, a highly talented writer/producer named Audrey Gellen, was killed in an automobile accident. Their only child, John Michael, is a skilled pianist.