The set of books I have I think were printed during 1954, by Cassell & Sons, however it is a set.
Think you may be looking for a first edition on the last volume,
First edition (hardcover) in six volumes
- The Gathering Storm (1948)
- Their Finest Hour (1949)
- The Grand Alliance (1950)
- The Hinge of Fate (1950)
- Closing the Ring (1951)
- Triumph and Tragedy (1953) (Prefix by Churchill 30th September 1953)
You may only find the volumes your looking for in the USA, found this on wiki.
The Second World War has been issued in editions of six, twelve and four volumes, as well as a single-volume abridgment. Some volumes in these editions share names, such as
Triumph and Tragedy but the contents of the volumes differ, covering varying portions of the book.
The country of first publication was the United States, preceding publication in the United Kingdom by six months. This was a consequence of the many last minute changes which Churchill insisted be made to the London Cassell edition, which he considered to be definitive.