Code-switching, the alternating use of two languages in the same stretch of discourse by a bilingual speaker – is a dominant topic in the study of bilingualism and a phenomenon that generates a great deal of pointed discussion in the public domain. This handbook provides the most comprehensive guide to this bilingual phenomenon to date. Drawing on empirical data from a wide range of language pairings, the leading researchers in the study of bilingualism examine the linguistic, social, and cognitive implications of code-switching in up-to-date and accessible survey chapters.