José or Joseph Penso de la Vega, best known as Joseph de la Vega, was a Sephardic Jewish merchant in diamonds, financial expert, moral philosopher and poet, residing in Amsterdam. He became famous for his masterpiece Confusion of Confusions. Vega's work is the first study written about the Amsterdam Stock Exchange and its participants, the shareholders. In a stilted style he describes the whole gamut, running from options, futures contracts, margin buying, to bull and bear conspiracies, even some form of stock-index trading. The publication of Confusión de Confusiones helped lay the foundations for modern fields of technical analysis and behavioral finance.