Since Juan Uriagereka originated the multiple spell-out model in 1999 it has been one of the most influential lines of research in syntactic theorizing. The model simplified a crucial element of the minimalist account of language making it a more accurate reflection of syntax and its acquisition. In this book he explores important consequences of the multiple spell-out hypothesis and of the linked notion of cyclicity. He combines the latest thinking in linguistics with perspectives drawn from physics, biology, and animal behaviour, aiming thereby to advance the field first described by Noam Chomsky as biolinguistics. Without simplifying them Professor Uriagereka seeks to present the issues and their broader biological significance clearly and succinctly in ways that are accessible to scholars from adjacent fields with a limited background in linguistics. His analogies and comparisons between linguistic and non-linguistic phenomena (such as the syntax of birdsong) will be of value to both non-linguists and linguists, whose overriding concerns with narrow linguistic questions may sometimes obscure their broader biological significance. The subjects discussed in the book include the linearization of structure, the punctuated nature of a derivation (the multiple spell-out model), cyclicity and its consequences for locality, and the definition of c-command and its relevance to various types of grammatical dependency. The author discusses the evolutionary implications of his work, considering, for example, whether the punctuated nature of the derivation is a resolution of conflicting demands that yield an equilibrium found in nature more generally. This groundbreaking book will appeal to a wide range of readers in linguistics and cognitive science.