The best part about this book is the way Mazis brings everything to the table. He is not afraid to include new discoveries or advances in science and psychology for his philosophical analysis. By digging into the three realms of Humans, Animals, and Machines, Mazis challenges us as readers to do the philosophizing. The book is organized in a way that compares and analyzes the three realms both separately as well as together, so that the reader has multiple angles from which to sort out the "boundaries." As a student of philosophy, I am always striving to learn more about humanity. After reading this book, I was most surprised to learn about humanity from the study of machines and animals rather than humans themselves. Mazis' conclusion is both controversial as well as present minded. He is realistic about the world we live in, pragmatic rather than idealistic, offering suggestions for the betterment of our community in which we all coexist, human, animal, and machine alike.