This enjoyable, informative book would serve as an excellent introductory text in a beginning course on language acquisition or linguistics. The content is somewhat narrower than the title suggests: The book deals exclusively with L1 acquisition, and its focus is Chomskyan syntax and Universal Grammar, with a bit of semantics presented toward the end (i.e., phonology is not addressed). Most of the data is from English, though other languages are explored (e.g., French, Japanese), with three very interesting chapters on American Sign Language.