This is the first book of its kind to bring together a diverse set of human and nonhuman animal researchers to explore neurobehavioral trait dimensions with optimal relevance to mental illness: threat sensitivity, reward sensitivity, inhibitory control, affiliative capacity, and schizotypy. The volume presents foundational material, methodological considerations, and the integration of animal and human studies, providing a careful investigation of neurobehavioral trait dimensions. A special feature is the inclusion of paired chapters contrasting animal and human studies that demonstrate the state of the field. It also discusses the most promising neurobehavioral trait dimensions for understanding the processes associated with human mental illness. This integrated perspective fosters a deeper understanding of how individual differences in neurobiology contribute to the diversity of human behavior and the complex nature of mental health disorders. Taken together, insights into neurobehavioral traits promise to catalyze new research directions, inform policy decisions, and ultimately improve outcomes for individuals grappling with mental illness.