Book excerpt: The Five Factor Model, which measures individual differences on extraversion, agreeableness, conscientiousness, emotional stability, and openness to experience, is arguably the most prominent dimensional model of general personality structure. In fact, there is now a considerable body of research supporting its construct validity and practical application in clinical, health, and organizational settings. Taking this research to the forefront, The Oxford Handbook of the Five Factor Model showcases the work of expert researchers in the field as they each offer important insight and perspective on all that is known about the Five Factor Model to date. By establishing the origins, foundation, and predominance of the Five Factor Model, this Handbook will focus on such areas as construct validity, diagnosis and assessment, personality neuroscience, and how the Five Factor Model operates in business and industry, animal personality, childhood temperament, and clinical utility.