This is a popular science book, designed as a sequel to our About Life, though readers need not be familiar with the earlier volume. Indeed, no specialist knowledge is required. The text briefly surveys the nature of science and its emergence in post-Renaissance Europe, and investigates the similarities and differences between biology and other sciences. Major topics in the philosophy of biology (e.g. evolutionary theory, vitalism/mechanism, reductionism/holism, spontaneous generation) are considered in a little more detail.