This classroom-tested volume aspires to be a brief but technically and factually accurate exposition of linguistic description and history. Whether studied as prime subject or as background information, it should help students understand the assumptions and reasoning that underlie the contents of their handbooks and etymological dictionaries. This book should be a useful guide for anyone unfamiliar with (historical) linguistics who is studying the history of a language, and also for those who are enrolled in courses devoted to reading texts in old languages.