Bill M. Williams (1932–2019)[1] was an American trader and author of books on trading psychology, technical analysis, and chaos theory[2] in trading the stock, commodity, and foreign exchange (Forex) markets. His study of stock market data led him to develop a number of technical analyses that identify trends in the financial markets. Indicators like Accelerator/Decelerator Oscillator, Alligator indicator,[3] Awesome Oscillator, Fractals indicator,[4] Gator Oscillator, and Market Facilitation Index are popular today in Forex, stock, and other financial markets.