This volume describes how well we maintain the knowledge we acquire throughout life. Research traditionally focuses on memory for events that are retained over short time periods that can be accommodated in experiments. This book, by contrast, uniquely describes the evolution of methods suitable for investigating memory of complex knowledge acquired over several years and retained during the entire life-span. The methods substitute statistical for experimental controls, and the investigations involve several hundred participants whose memory is tested up to 50 years after they acquired the...