This volume provides a sample of the most recent studies on Spanish-English codeswitching both in the Caribbean and among bilinguals in the United States. In thirteen chapters, it brings together the work of leading scholars representing diverse disciplinary perspectives within linguistics, including psycholinguistics, sociolinguistics, theoretical linguistics, and applied linguistics, as well as various methodological approaches, such as the collection of naturalistic oral and written data, the use of reading comprehension tasks, the elicitation of acceptability judgments, and computational methods. The volume surpasses the limits of different fields in order to enable a rich characterization of the cognitive, linguistic, and socio-pragmatic factors that affect codeswitching, therefore, leading interested students, professors, and researchers to a better understanding of the regularities governing Spanish-English codeswitches, the representation and processing of codeswitches in the bilingual brain, the interaction between bilinguals' languages and their mutual influence during linguistic expression.