Peter Lewyn Bernstein (January 22, 1919 – June 5, 2009) was an American financial historian, economist and educator whose development and refinement of the efficient-market hypothesis made him one of the country's best known authorities in popularizing and presenting investment economics to the general public. Education and military service during World War II A native of New York City, Peter Bernstein was the son of financial consultant Allen Bernstein and his wife, Irma Lewyn. His primary education was at the Ethical Culture School where, in first grade, he became a lifelong friend of another renowned economics historian, Robert Heilbroner, with whom he later attended Horace Mann School and Harvard College, from which both received, in 1940, bachelor's degrees in economics. Following Harvard, where he was elected to Phi Beta Kappa and graduated magna cum laude, came service as a member of the research staff at the Federal Reserve Bank of New York and, in a civilian capacity, at the Office of Strategic Services in Washington. In the aftermath of the December 7, 1941 Pearl Harbor attack, he joined the Air Force and rose to the rank of captain, assigned to the Office of Strategic Services in the European theater. As investment manager In 1951, after teaching economics at Williams College and a five-year stint in commercial banking, Bernstein took over, at family insistence, the management of his late father's wealth management firm, Bernstein-Macaulay Inc., where he personally managed billions of dollars of individual and institutional portfolios. The assets under his management had grown more than tenfold by the time the firm was sold in 1967 and he resigned in 1973 to launch Peter L. Bernstein, Inc. and, a year later, to become the first editor of The Journal of Portfolio Management, a widely read scholarly financial publication for investment managers and academics. He continued as consulting editor of the Journal and served on the advisory panel of Robert D. Arnott's investment management firm, Research Affiliates. Career as educator and lecturer Bernstein served for many years on the Visiting Committee to the Economics Department at Harvard University, as a Trustee and member of the Finance Committee of the College Retirement Equities Fund (CREF), and as a Trustee of the Investment Management Workshop sponsored by the Association for Investment Management & Research (AIMR), and had been lecturing widely throughout the United States and abroad on risk management, asset allocation, portfolio strategy, and