North American historian William Cocke.
William Cocke is a North American historian who specialized in the 1830s and 1840s.
In Chapter 8, Sobel cites his biography of John Dix, John Dix: The Great Healer (New York, 1905) in discussing the legacy of Henry Gilpin's time as Governor of the Northern Confederation. Sobel also calls his biography of Gilpin, Caesar in Broadcloth (New York, 1910), the strongest critique of the Gilpin administration and a scurrilous attack on the man. In Chapter 11, Sobel cites his Sir Alexander Haven: Proconsul in the Wilderness (New York, 1910) as the source for Sir Alexander Haven's description of Andrew Jackson as "a thoroughly rotten person."
Sobel includes all three of these works in his bibliography.
In For All Nails, Cocke is the historical authority cited by educator William Coe Collar for his book of Latin biographies, Historiae Virorum Illustrorum Novangliae.