The ill-fated mountaineer George Mallory's only book was "Boswell the Biographer"?
Friedrich Karl von Forster
Sometime (until 1763 or 1764) chamberlain and privy counsellor of legation at the court of Saxe-Gotha and from March 1, 1764 chief steward of that court.1
Life with Boswell:
Note 1: Only source for this biography is The Journal of his German and Swiss Travels, 1764.