Necessary Doubt (1964), Colin Wilson’s fifth novel, is a compelling metaphysical thriller which shows the conversion of its elderly protagonist from Christianity to evolutionary optimism. Wilson originally wrote it as a TV play but turned it into a novel when it did not get produced (the script was finally published in 2008). By Wilson’s own account, Necessary Doubt was influenced by the fiction of the Swiss playwright, novelist and critic Friedrich Dürrenmatt (1921-90). In one of his literary critical studies, The Strength to Dream: Literature and the Imagination (1962), Wilson had praised Dürrenmatt as a writer, especially his novel Das Versprechen (The Pledge (1958)), …
Tredell, Nicolas. "Necessary Doubt". The Literary Encyclopedia. First published 24 June 2008; last revised 30 November -1.
[http://www.litencyc.com/php/sworks.php?rec=true&UID=23921, accessed 21 April 2015.]