This volume presents seven extensive essays by specialists in their respective fields of historical linguistics. The first essay after the Introduction states the principles presented in Directions for Historical Linguistics (1968) and assesses the progress made since then towards constructing a general theory of language change. Like the following essays on phonology and morphology, it poses new questions that have arisen in the increasingly ambitious research. Historical attention to discourse, the topic of the next essay, is virtually new, though it too finds predecessors among philo