Here is a universal biology that draws upon the contributions of Aristotle, Kant, and Hegel to unravel the mystery of life and conceive what is essential to living things anywhere they may arise. The book develops a philosopher’s guide to life in the universe, conceiving how nature becomes a biosphere in which life can emerge, what are the basic life processes common to any organism, how evolution can give rise to the different possible forms of life, and what distinguishes the essential life forms from one another.