Develops a new theory of focus structure, exploring the role of focusing in natural language sentence.All modes of perception (vision, hearing, etc) are organised into foreground or focus and background constituents. Natural language sentences are no different. This book explores the role of focusing in natural language sentences and the role of this basic cognitive mechanism in explaining sentence stress, meaning and structure. The result is an innovative view of our linguistic competence.All modes of perception (vision, hearing, etc) are organised into foreground or focus and background constituents. Natural language sentences are no different. This book explores the role of focusing in natural language sentences and the role of this basic cognitive mechanism in explaining sentence stress, meaning and structure. The result is an innovative view of our linguistic competence.All modes of perception (vision, hearing, etc.) are organized into foreground or focus and background constituents. Natural language sentences are no different. This book explores the role of focusing in natural language sentences and the role of this basic cognitive mechanism in explaining sentence stress, meaning and structure. The result is an innovative view of our linguistic competence.Introduction; 1. The interpretation of f-structure; 2. Reference and coreference; 3. Negation, questions and contrast; 4. The phonological interpretation of f-structure; 5. Scope and R-dependencies; 6. I-dependencies in focus-structure; Conclusion; References; Indexes.