Sir John Harold Plumb (1911–2001) was a preeminent historian who wrote primarily on the 18th century and authored 35 books. At the start of World War II, he left Cambridge University to work at the top secret Bletchley Park facility, where he headed a section working on a German Naval hand cipher, Reservehandverfahren. After the War he became a Fellow of Christ's College at Cambridge, and was named Master of the College from 1978 to 1982. For American Heritage, Plumb wrote The Italian Renaissance (1961) and co-authored the American Heritage Book of the Revolution. Among his other books are England in the Eighteenth Century, The First Four Georges, The Penguin Book of the Renaissance, and Royal Heritage: The Treasures of the British Crown.