From Bruce Schneier’s “Brandeis Quote on Openness“:
Louis D. Brandeis, Other People’s Money and How the Bankers Use It 92 (1914): “Publicity is justly commended as a remedy for social and industrial diseases. Sunlight is said to be the best of disinfectants; electric light the most efficient policeman.”
[Note: Also in Harper’s Weekly, Dec 20 1913]