In 1981, George Brooks provided a review of the academic discipline of physical education and its emerging subdisciplines. Forty years later, the authors review how the field has changed from the perspective of one subdiscipline, motor development. Brooks’s text sets the scene with four chapters on motor development from leaders in the field, including G. Lawrence Rarick, to whom the book is dedicated. From this beginning, the paper describes the evolving scientific perspectives that have emerged since 1981. Clearly, from its past to the present, motor development as a scientific field has itself developed into a robust and important scientific area of study. The paper ends with a discussion of the grand challenges for kinesiology and motor development in the next 40 years.