This book is a study in universal grammar. It attempts to find a set of constraints which limits the applicability of syntactic transformations of two types; rules called chopping rules, which reorder some part of sentence, and rules of influence. The major theoretical notion that is developed is that of islands; autonomous domains of the tree structures that underlie sentences. While the book is primarily an investigation within the subfields of generative syntax, it should also be of interest to cognitive scientists, philosophers of language, and social scientists.