This book is a unique work by Edmund W. Sinnott, combining biology and philosophy in an attempt to understand major human problems from a scientific perspective. The author argues that humans are organic beings, and everything about them, including aspects of spiritual life, is rooted in the biological processes that underlie their existence. According to Sinnott, biology goes beyond the study of the biological makeup of organisms and the evolutionary history of animals and plants, moving beyond these fields toward a deeper understanding of life's problems, which are essentially biological problems. Sinnott argues that all areas of human nature are linked by a central biological fact: the "self-regulation" of living things. He describes this phenomenon as a kind of goal-directedness, manifested in the behavior of living organisms as they grow and develop with precise discipline, suggesting a kind of consciousness or "biological intentionality." This connection between mental processes and organic makeup is what the author seeks to explain, relying on scientific evidence to support this conception. The book addresses several topics, such as the dual nature of man, biological goals, and human motivations, all the way to the philosophy of goals and the vitality of the soul. Through this blend of science and philosophical thought, Sinnott offers a new and profound vision of man's relationship with nature, attempting to explore the soul through the lens of science.