The document is a chapter from an Industrial-Organizational (I-O) psychology textbook. It provides an overview of the field of I-O psychology, including its history, key topics, research methods, and contemporary challenges. Some of the major areas discussed include the origins of I-O psychology, the Hawthorne studies, psychological testing during World War I and II, common jobs and salaries for I-O psychologists, and problems faced in the field such as fraudulent practitioners.