Mark Twain, William Dean Howells (1960). “Mark Twain-Howells Letters: The Correspondence of Samuel L. Clemens and William D. Howells, 1872-1910”, Belknap Press
On Active Service in Peace and War ch. 7 (1948). Stimson was explaining his action, while secretary of state in 1929, in closing the State Department's codebreaking office. The 1948 book, coauthored with McGeorge Bundy, is the earliest known appearance of this quotation. Louis Kruh, in his article "Stimson, the Black Chamber, and the 'Gentleman's Mail Quote," Cryptologia, Apr. 1988, concludes that these words accurately represented Stimson's feelings in 1929 but that "whether he also said it the