This groundbreaking book offers a new and compelling perspective on the structure of human language. The fundamental issue it addresses is the proper balance between syntax and semantics, between structure and derivation, and between rule systems and lexicon. It argues that the balance struck by mainstream generative grammar is wrong. It puts forward a new basis for syntactic theory, drawing on a wide range of frameworks, and charts new directions for research. In the past four decades, theories of syntactic structure have become more abstract, and syntactic derivations have become ever more complex. Peter Culicover and Ray Jackendoff trace this development through the history of contemporary syntactic theory, showing how much it has been driven by theory-internal rather than empirical considerations. They develop an alternative that is responsive to linguistic, cognitive, computational, and biological concerns. At the core of this alternative is the Simpler Syntax Hypothesis: the most explanatory syntactic theory is one that imputes the minimum structure necessary to mediate between phonology and meaning. A consequence of this hypothesis is a far richer mapping between syntax and semantics than is generally assumed. Through concrete analyses of numerous grammatical phenomena, some well studied and some new, the authors demonstrate the empirical and conceptual superiority of the Simpler Syntax approach. Simpler Syntax is addressed to linguists of all persuasions. It will also be of central interest to those concerned with language in psychology, human biology, evolution, computational science, and artificial intellige.