Elbert Hubbard (1856–1915), U.S. author. The Motto Book (1907), repr. In Selected Writings, vol. 1, "Index" (1921).
The saying found an echo in P.G. Wodehouse's short story, The Man Upstairs (1914): "It is a good rule in life never to apologise. The right sort of people do not want apologies, and the wrong sort take a mean advantage of them." Earlier, Benjamin Disraeli is quoted, "Never complain and never explain." (John Morley, Life of Gladstone, vol. 1, 1903).