Where did we come from before birth? Where are we going after death? What is the meaning of life? What is the responsibility of life? Many practitioners, scholars, and experts have searched for answers to these questions about life since ancient times. And many of them have provided the results of such investigations. The Tibetan Book of Living and Dying is an example of this. This book offers many perspectives and insights on life and death so that this thesis will explore the wisdom of life and death mentioned in that book. Only when we know and recognize the real knowledge of life and death can we know where life's responsibility lies in our lives; only then can we move towards the ultimate fulfillment of life. This essay begins with the phenomenon of life to explore life's nature and then explains the creation and realization of life's value. The necessity of spiritual practice is thus sorted out. Secondly, from the core and truth of life - eternity, perfection, and oneness with all things - we discover how we can take responsibility for life through spiritual practice and find proper ways to bring ourselves to the state of perfection. Finally, on death, we study death and its process through the various stages of the Bardo and then find out the more in-depth and complete meaning of death to gain an in-depth understanding of death. The Tibetan Book of Living and Dying expects people to understand life and death, understand the true meaning of life, and help the dying. This thesis focuses on an academic investigation of the wisdom of life and death discussed in this book, especially on the subject's responsibility in life when this wisdom is practiced in daily life. This thesis summarizes these responsibilities of life and proposes specific and workable solutions in the hope of achieving some or even total liberation for those who are deeply bound by karma so that individuals and groups can settle down in the present and create a new and perfect rationale reality in the future.