The original study on delay of gratification was conducted by Dr. Walter Mischel, who recruited hundreds of preschoolers from the Bing nursery school at Stanford University in the late '60s. Two follow-ups of the original sample, first in high school and then in college, showed that the number of seconds that preschoolers were able to delay gratification significantly predicted diverse social-cognitive outcomes years later. Impressed by these longitudinal findings, Daniel Goleman, a science writer at New York Times, popularized this concept as an aspect of Social Intelligence and Emotional Intelligence. I was given the opportunity to study the original Bing sample while I was a graduate student at UC Berkeley. Most of the original participants are now entering into middle adulthood and many of them have children of their own. This book reports new findings linking delay of gratification to new outcomes in later stages of life. The primary contribution of this work is that it extends the stability of delay of gratification from preschool to 40 years of age. In addition, my work proposes an instrument to measure adults' ability to delay gratification.