Let us pause in the day’s labors to raise a glass, preferably containing Madeira or a rich, full-bodied port, to the centenary of the greatest historical novelist ever, and one of the best novelists of our era.

Patrick O’Brian was born Dec. 12, 1914—or, rather, Richard Patrick Russ was born on that date in Chalfont St. Peter, England, and grew up to become a novelist of middling success. O’Brian was technically born in 1946, when Russ adopted that pen name and went on to develop a new persona as an elusive Irish writer ensconced...