Warren Buffett is an American business magnate, investor, and philanthropist, serving as chairman and CEO of Berkshire Hathaway since 1970. Renowned for his value investing approach, Buffett has built Berkshire into a diversified conglomerate with holdings in insurance, energy, manufacturing, and consumer goods. Often called the 'Oracle of Omaha,' he is widely regarded as one of the most successful investors in history and has pledged much of his wealth to philanthropic causes.