This book presents a collection of linked essays written by one of the leading philosophers of biology, Kim Sterelny, on the topic of biological evolution. The first half of the book explores most of the main theoretical controversies about evolution and selection. Sterelny argues that genes are not the only replicators: non-genetic inheritance is also extremely important, and is no mere epiphenomenon of gene selection. The second half of the book applies some of these ideas in considering cognitive evolution. Concentrating on the mental capacities of simpler animals rather than those of humans, Sterelny argues for a general distinction between detection and representation, and that the evolution of belief, like that of representation, can be decoupled from the evolution of preference. These essays, some never before published, form a coherent whole that defends not just an overall conception of evolution, but also a distinctive take on cognitive evolution.