George Donald King McCormick (11 December 1911 – 2 January 1998) was a British journalist and popular historian, who also wrote under the pseudonym Richard Deacon.
This is a fine general overview type of book ... just a paragraph or two on many agents and intelligence officers through the years. I wouldn't quote from it, however, as it is unreliable in details, at least in the areas of interest to me. The entry for Dusko Popov, for example, has numerous errors.