Henry Alfred Kissinger (born Heinz Alfred Kissinger, May 27, 1923) is an American diplomat and political scientist. He served as National Security Advisor and later concurrently as Secretary of State in the administrations of Presidents Richard Nixon and Gerald Ford. For his actions negotiating the ceasefire in Vietnam (though never realised), Kissinger received the 1973 Nobel Peace Prize under controversial circumstances, with two members of the committee resigning in protest. After his term, his advice has still been sought by many subsequent U.S. presidents and other world leaders. A proponent of Realpolitik, Kissinger played a prominent role in United States foreign policy between 1969 and 1977. During this period, he pioneered the policy of détente with the Soviet Union, orchestrated the opening of relations with the People's Republic of China, and negotiated the Paris Peace Accords, ending American involvement in the Vietnam War. Kissinger's Realpolitik resulted in controversial policies such as CIA involvement in Chile and U.S. support for Pakistan, despite its genocidal actions during the Bangladesh War. He is the founder and chairman of Kissinger Associates, an international consulting firm. Kissinger has been a prolific author of books on politics and international relations with over one dozen books authored. Some scholars have ranked Kissinger as the most effective U.S. Secretary of State in the last 50 years.