This is a thoroughly revised, updated and expanded edition of Ralph Penny's authoritative textbook, first published in 1991, which provides a clear and elegant account of the development of Spanish over the last 2,000 years. Although principally oriented towards 'internal' history, 'external' history is also considered and referred to throughout. In this new edition, as well as adding insights from recent scholarship throughout the text, Professor Penny has added a new chapter which discusses the nature of linguistic history, the concept or world Spanish, processes of convergence and divergence in Spanish, and the English-Spanish interface. This edition also contains a glossary of technical terms, guidance on further reading and suggested topics for discussion.