This book is an introduction to historical linguistics - the study of language change over time. Written in an engaging style and illustrated with examples from a wide range of languages, the book covers the fundamental concepts of language change, methods for historical linguistics, linguistic reconstruction, sociolinguistic aspects of language change, language contact, the birth and death of languages, language and prehistory and the issue of very remote relations. The book is thoroughly up to date, and covers the most recent work on the study of phonological changes in progress, on morphological and syntactic change, and on typological approaches to change. It also addresses such recent controversies as the Nostratic hypothesis and the Greenberg/Cavalli-Sforza work on language, genes and teeth. A minimal knowledge of linguistic concepts is needed and the book is suitable for students approaching the subject for the first time. The exercises will be particularly useful to teachers and students alike. The approach is data-oriented throughout and students are encouraged to confront data, to spot patterns and to draw on their own knowledge of languages.