Historical linguistics is the study of how and why language changes--both the methods of investigating language change and the theories designed to explain these changes. This accessible introductory text takes a hands-on, how-to approach, rather than just talking about the subject as many texts do. The book contains examples both from familiar European languages, to make the topics accessible, and from a variety of non-European languages, to illustrate the depth and range of the concepts. The book also covers a number of topics neglected by most texts, including syntactic change, methods for investigating distant genetic relationship, linguistic prehistory, and grammaticalization.