Robert Brandon is one of the most important and influential of contemporary philosophers of biology. This collection of his recent essays covers all the traditional topics in the philosophy of evolutionary biology and as such could serve as an introduction to the field. There are essays on the nature of fitness, teleology, the structure of the theory of natural selection, and the levels of selection. The book also deals with newer topics that are less frequently discussed but are of growing interest, e.g. the evolution of human language and the role of experimentation in evolutionary biology.