This book brings together the different strands and styles of research on Phi-features, such as person, number, and gender. It presents the core questions, major results, and new directions of this area of linguistic theory and shows how Phi Theory casts light on the nature of interfaces and the structure of the grammar.

1. Why Phi? ; 2. Features on Bound Pronouns ; 3. On the Semantic Markedness of Phi Features ; 4. Phi-Agree and Theta-Related Case ; 5. Conditions on Phi-Agree ; 6. Phi Feature Competition in Morphology and Syntax ; 7. Discontinuous Agreement and the Syntax Morphology Interface ; 8. Third Person Marking in Menominee ; 9. When is a Syncretism More Than a Syncretism? ; 10. Where's Phi? Agreement as a Post Syntactic Operation ; 11. Cross-Modular Parallels in the Study of Phon and Phi

Daniel Harbour is a Research Fellow at Queen Mary, University of London. His primary research interest is features, from interpretation to pronunciation. His publications include Morphosemantic Number (Springer 2007) and An Intelligent Person's Guide to Atheism (Duckworth 2001). David Adger is Professor of Linguistics at Queen Mary, University of London. He is author of Core Syntax (OUP 2003) and co-editor of the journal Syntax. His publications on syntax and its interfaces with other components of the grammar include articles in Language, Linguistic Inquiry and Natural Language and Linguistic Theory. Susana Béjar is a Lecturer in Linguistics at the University of Toronto. Her research investigates complexity in morphosyntactic systems. Her book, Phi-Syntax: A Theory of Agreement, is in preparation for publication in this series.