This is a collection of essays on the history and philosophy of evolutionary biology by the well-known Canadian scholar, Michael Ruse. Much has been written newly for the collection, as the author explores themes of evolutionary naturalism, putting the theory of knowledge and of moral behaviour on a philosophical basis informed by contemporary evolutionary biology. Divided into three parts, the first set of essays considers issues in the history of science - Darwin, population biology, and the new paleontological theory of `punctuated equilibria' - attempting to find a path between the crude objectivity espoused by many working scientists, and the rank relativism of post-modernist critiques of science. The second set of essays turns directly to the theory of knowledge (epistemology), arguing that the fact that we are evolved beings rather than objects of special creation, must and does inform our thinking about the external world. The third set of essays, the most controversial, turns to questions of morality, arguing that ethical systems are ultimately no more than collective illusions put in place by our biology, because humans are essentially social animals. Written in a clear and non-technical fashion, this collection carries forward debate on a number of controversial issues, showing that the time has now come to take philosophy from the hands of academic theorists and to embrace fully the findings and consequences of modern science.