This book offers a 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 more complex. The book traces this development through the history of contemporary syntactic theory, showing how much it has been driven by theory-internal rather than empirical considerations. It develops 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 richer mapping between syntax and semantics than is generally assumed. Through analyses of grammatical phenomena, some old and some new, the book demonstrates the empirical and conceptual superiority of the Simpler Syntax approach.