Life Span Development is an area of psychological research. It looks at an individual's journey from birth to death and the challenges along the way. I can't think of a more important topic. Consequently, this book will discuss Life Span Development from multiple perspectives. It will look at it from the perspective of my martial arts teacher, Daniel Yu Wang. Daniel survived the Cultural Revolution, one of the great tragedies of the modern era. It will look at this topic from a philosophical perspective, the theory of yin and yang and the martial art it inspired, Tai Chi Chuan. Finally, it will look at life span from a common sense and psychological perspective. Hopefully, these multiple lenses will give the reader a deeper understanding of what it means to be fully human.