Bybee has been arguing for decades that frequency is crucial for understanding how language structure emerges from usage. The papers in this collection deal with phenomena from sound patterns to syntax. Some of the proposals are radical indeed. For example, Bybee claims that constituent structure can't be simply stipulated, it has to be explained, and the explanation is to be found in the fact that semantics/pragmatics are responsible for sequentiality or linear order, while frequency creates the tight bonds typical of 'syntactic structure.' In recent years, these ideas have become increasingly prominent in empirical and theoretical approaches to language, and constitute a significant challenge to more traditional conceptions. Highly recommended.