Peter Maurice Wright was an English scientist and former MI5 counterintelligence officer, noted for writing the controversial book Spycatcher, which became an international bestseller with sales of over two million copies. Spycatcher was part memoir, part exposé of what Wright claimed were serious institutional failings in MI5 and his subsequent investigations into those. He is said to have been influenced in his counterespionage activity by James Jesus Angleton, the US Central Intelligence Agency (CIA) counterintelligence chief from 1954 to 1975.