Among the most prolifically treated topics in grammaticalization approaches to semantic change is the development of periphrastic past constructions, particularly the 'have'-perfects in Romance and other Indo-European languages. This issue is an intriguing one for language researchers since it offers the opportunity to observe language change both as an incipient process that involves the transition of some lexical element into a more 'grammatical' role as well as a process of semantic generalization without the necessity of overt structural reorganization. This book explores the development of the periphrastic past (or preterito perfecto compuesto) in Spanish, with special attention to its cross-dialectal distribution vis-a-vis the simple perfective past (or preterito), and assumes a multi-disciplinary perspective, drawing on insights from semantic and pragmatic as well as sociolinguistic approaches to language change. The resulting proposals, developed on the basis of spoken language data from cross-dialectal samples of Spanish, address the nature of language change and the variable forces that shape it.