Seymour Myron "Sy" Hersh is an American investigative journalist and political writer. He gained recognition in 1969 for exposing the My Lai massacre and its cover-up during the Vietnam War, for which he received the 1970 Pulitzer Prize for International Reporting. During the 1970s, Hersh covered the Watergate scandal for The New York Times, also reporting on the secret U.S. bombing of Cambodia and the Central Intelligence Agency's (CIA) program of domestic spying. In 2004, he detailed the U.S. military's torture and abuse of prisoners at Abu Ghraib in Iraq for The New Yorker. Hersh has won a record five George Polk Awards, and two National Magazine Awards. He is the author of 11 books, including The Price of Power: Kissinger in the Nixon White House (1983), an account of the career of Henry Kissinger which won the National Book Critics Circle Award.

The My Lai massacre was a war crime committed by United States Army personnel on 16 March 1968, involving the mass murder of unarmed civilians in Sơn Tịnh district, South Vietnam, during the Vietnam War. Between 347 and 504 civilians were killed by U.S. soldiers from Company C, 1st Battalion, 20th Infantry Regiment and Company B, 4th Battalion, 3rd Infantry Regiment, 11th Brigade, 23rd (Americal) Infantry Division. Victims included men, women, children, and infants. Some of the women were gang-raped and their bodies mutilated, and some soldiers mutilated and raped children who were as young as 12. It is the largest publicized massacre of civilians by U.S. forces in the 20th century.