Originally published in 1975, this book provides a detailed analysis of the way in which inferences about the evolutionary history of human populations may be made from genetic data of modern populations. The pattern of genetic differentiation between human populations reflects and therefore contains information about their evolutionary history. A statistical model for the genetic evolution of populations is set up so that estimates of the evolutionary history may be made. Problems of scientific inference arise in the interpretation of the model and its results and many points of interest in the theory of the foundations of inference are illustrated. The likelihood approach is adopted; hypotheses of evolutionary history are judged on their relative ability to explain the data. This book will be of value to anyone with an interest in human evolution and genetic data.