Benjamin Graham — American Economist born on May 08, 1894, died on September 21, 1976

Benjamin Graham was a British-born American economist and professional investor. Graham is considered the father of value investing, an investment approach he began teaching at Columbia Business School in 1928 and subsequently refined with David Dodd through various editions of their famous book Security Analysis. Graham had many disciples in his lifetime, a number of whom went on to become successful investors themselves. Graham's most well-known disciples include Warren Buffett, William J. Ruane, Irving Kahn and Walter J. Schloss, among others. Buffett, who credits Graham as grounding him with a sound intellectual investment framework, described him as the second most influential person in his life after his own father. In fact, Graham had such an overwhelming influence on his students that two of them, Buffett and Kahn, named their sons Howard Graham Buffett and Thomas Graham Kahn after him. Graham also taught at the UCLA Anderson School of Management... (wikipedia)

Most of the time common stocks are subject to irrational and excessive price fluctuations in both directions as the consequence of the ingrained tendency of most people to speculate or gamble... to give way to hope, fear and greed.
Wall Street people learn nothing and forget everything.