First Published in 1998. This book is a revision of the author's 1995 University of Edinburgh dissertation entitled X° Categories and Grammatical Case Assignment in Finnish . This work provides a structural account for patterns of grammatical case in Finnish within the Principles and Parameters framework. The rich case and agreement morphology of Finnish make it an important language for testing hypotheses about the relationships between morphological case and abstract Case, and Case/case and agreement. In particular, several case 'splits' occur in Finnish which challenge standard theoretical accounts about the relationship between abstract and morphological case.