… is from page 205 of the 1992 collection of some of William Graham Sumner’s best essays, On Liberty, Society, and Politics  (Roger C. Bannister, ed.); specifically, this quotation is from Sumner’s famous 1883 essay “The Forgotten Man “:
All history is only one long story to this effect: men have struggled for power over their fellow-men in order that they might win the joys of earth at the expense of others and might shift the burdens of life from their own shoulders upon those of others.
Sumner’s statement offers an important truth, but it is a truth that his here somewhat overstated. It’s not literally all history – but it is in fact most of history. Fortunately for those of us in the modern, commercial world, some history is a story of trade and of the cooperation that it entails and of the creative destruction that trade and commerce have inspired over the past two or three centuries. Unfortunately for all of humankind, trade and commerce and innovation are typically viewed with some mixture of fear and contempt. Those people who make their living by devising and offering better mousetraps to willing buyers are too often portrayed as villains, while those other people who promise to forcibly take the fruits of the mousetrap factories from their creators and ‘re-distribute’ those fruits to the masses are portrayed as heroes.