On September 21, 1976, the secret police of the Chilean dictator Augusto Pinochet assassinated Orlando Letelier, a former ambassador and a leader of the opposition in exile, and his colleague, Ronni Moffitt, in broad daylight on Embassy Row, in Washington, D.C. Drawing heavily on previously published accounts, McPherson retraces the many twists and turns of the lengthy joint U.S.-Chilean investigation to identify and prosecute the perpetrators. The brazen violation of American national sovereignty, McPherson argues, as much as the violation of human rights, shook the U.S. government. The Letelier case established important precedents in international human rights law. There are many heroes in this account, including tenacious U.S. government attorneys, alert U.S. diplomats, and dogged pro bono lawyers, but Letelier’s widow, Isabel, stands out for her intrepid, relentless activism. Arguably, the strong U.S. response served as a deterrent to other would-be political assassins: the killing of Letelier remains the only state-sponsored assassination of a foreign diplomat on U.S. soil.