In the growing field of address research, Spanish emerges as one of the most complex Indo European languages. Firstly, it presents second person variation in its nominal, pronominal, and verbal systems. Moreover, several Spanish varieties have more than two address variants, which compete and mix in intricate ways. This volume showcases current research into this unique linguistic situation, by presenting the original research of twelve scholars from a variety of theoretical and methodological perspectives. The articles cover diachronic change and regional variation, pragmatics, dialect contact, attitudes, and identity. The contributions are contextualized through an introduction and the responses of three established experts, while a conclusion delineates a research agenda for the future. This collection in English is meant to reach scholars beyond the confines of Hispanic linguistics.