There are still people, including some who should know better, who believe that American Sign Language is in some sense not a “real” language. Such a position, though perhaps at least debatable 40 years ago, is simply no longer credible. There has been a vast amount of very sophisticated and competent linguistic, psycholinguistic, and sociolinguistic research conducted on American Sign Language since the publication of William Stokoe's landmark book, Sign language structure (1960/1992). Although there are many areas of debate about specific features of the phonology, morphology, syntax, and so on of American Sign Language, as indeed is the case with every language, its fundamental status as a fully developed human language is now well beyond reasonable doubt. Since its first edition appeared in 1992, Valli and Lucas's Linguistics of American Sign Language: An introduction has been the premier work for students of the structure of American Sign Language. Written for students of linguistics who already have at least some knowledge of American Sign Language, this third edition includes sections introducing students to basic linguistic concepts, phonology, morphology, syntax, and semantics as well as issues related to language change, language variation, bilingualism, discourse, language contact, and “language as art.” Each section is designed to provide students with a general introduction to the linguistic concepts and then to the specific case of American Sign Language, including exercises focusing on American Sign Language. Finally, more than half of the volume is devoted to both classic and recent seminal articles about different aspects of the linguistics of American Sign Language. As has been true of both of the earlier editions, this third edition is accompanied by a well-made videotape providing additional support for the written text.