Simon Sinek is a British-born American author, speaker, and leadership expert. He is best known for his book Start with Why and his concept of the “Golden Circle,” which explores how leaders inspire action by defining their purpose before their process or product. Sinek has also written bestsellers including Leaders Eat Last and The Infinite Game, and is recognized for his influential TED Talk, “How Great Leaders Inspire Action,” one of the most viewed of all time.