<P>The authors of The Origins of Grammar have pioneered one of the most important methodological advances in language learning in the past decade: the intermodal preferential looking paradigm, which can be used to assess lexical and syntactic knowledge in children as young as thirteen months. They describe a theory of language learning that emphasizes the role of multiple cues and forces in development. They further show how infants shift their reliance on different aspects of the linguistic input, moving from a bias to attend to prosodic information to a reliance on semantic information, and finally to a reliance on the syntax itself.</P>