The Disciplined Trader: Developing Winning Attitudes by Mark Douglas is a seminal work that delves into the psychology of trading and the mental habits necessary for success in the financial markets. Douglas emphasizes that the key to successful trading lies not just in technical skills or strategies but in developing the right mindset and emotional discipline. He explores common psychological barriers that traders face, such as fear, greed, and self-doubt, and offers practical techniques to overcome them. Through insightful anecdotes and actionable advice, Douglas guides readers in cultivating a disciplined approach to trading, encouraging them to adopt a professional attitude toward their craft.