This book is an introduction to biophilosophy, written primarily for the student of biology, the practicing biologist, and the educated layperson. It does not presuppose technical knowledge in biology or philosophy. However, it requires a willingness to examine the most basic foundations of biology which are so often taken for granted. Furthermore, it points to the bottomlessness of these foundations, the mystery of life, the Unnamable .,. I have tried to further the awareness that biological statements are based on philosophical assumptions which are present in our minds even before we enter the laboratory. These assumptions, which often harbor strong commitments, are exposed throughout the book. I have tried to show how they influence concrete biolog ical research as well as our personal existence and society. Thus, emphasis is placed on the connection between biophilosophy and biological research on the one hand, and biophilosophy and the human condition on the other.