This book is based on taped morning-walk conversations that Srila Prabhupada had with some of his disciples during 1973, in the Los Angeles area. On those mornings when he focused on science, Srila Prabhupada spoke mainly with his disciple Thoudam D. Singh, Ph.D. An organic chemist, Dr. Singh presently directs the Bhaktivedanta Institute, an international center for advanced study and research in science, philosophy and theology.