What separates an investor from a speculator, and how can sound judgment survive an unpredictable market? This book approaches those questions through a framework that combines financial analysis with emotional discipline. Its opening material emphasizes that successful investing depends on a coherent method of making decisions and the ability to prevent feelings from undermining it. The chapters distinguish defensive investors from enterprising investors, developing different approaches to portfolio policy and stock selection. Inflation, historical stock prices, and market fluctuations provide a broader setting for decisions about common stocks. Readers are also introduced to investment funds, the relationship between investors and advisers, and security analysis for people without specialist training. Company comparisons and case histories give the discussion concrete analytical settings. Topics include earnings per share, convertible securities, warrants, dividend policy, and the relationship between shareholders and management. The margin of safety receives a dedicated concluding chapter and is identified as the central concept of investment. This revised edition pairs the original chapters with additional commentary, allowing readers to examine the principles alongside later discussion. Its appendixes address investment taxation, speculation in common stocks, technological companies, and investors associated with the Graham and Dodd approach. Across these subjects, the introductory pages encourage a businesslike response to market behavior: maintaining a reasoned framework while recognizing that emotional discipline remains the reader’s responsibility.