He spent the next 20 years working in newspapers, eventually becoming the political columnist for Cowles Publications.
In 1960, he wrote a chapter on John F. Kennedy for the book Candidates 1960. This seemed to ignite a passion for writing books and he turned his hand to book-length works.
He wrote fifteen books, most of them fiction, and all of them dealing with politics.
His best-known novel is Seven Days in May (1962), (co-written with Charles Bailey II), about an attempted military coup in the United States. The book was a huge success, staying at number one on the New York Times bestseller list for almost a year
Vanished (1968), about the political repercussions arising from the sudden, mysterious disappearance of the top aide to the President of the United States during a contentious re-election campaign
Trespass (1969), about blackmilitants taking over homes owned by rich whites and demanding that title be turned over to the militants as the first step in creating a black nation in the American South
Dark Horse (1972), about a minor official chosen to replace a Presidential candidate who died shortly before the election and
In general, Knebel's works are fun to read, but they are products of the times in which they were written. For instance, the delegate in Convention changes her vote after learning that the candidate she had originally favored is using a computer to track personal information about the delegates. Vanished involved concerns over superpowernuclear proliferation during the Cold War. Trespass revolves around black militancy of the type which faded in the late 1970s. As representations of the concerns of the times in which they were written, however, they can provide valuable insight.
Knebel was married four times from 1935 to 1985. He committed suicide after a long bout with cancer, by taking an overdose of sleeping pills in his home in Honolulu, Hawaii in 1993.
He is the source of the quote: "Smoking is one of the leading causes of statistics"
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