Syntactically speaking, it has long been known that noun phrases are parallel to clauses in many respects. While most syntactic theories incorporate this principle, nouns have generally been regarded as inferior to verbs in terms of their licensing abilities, and nominal projections have been regarded as less complex than verbal projections in terms of the number of functional categories that they contain. Ogawa, however, argues that clauses and noun phrases are perfectly parallel. This book provides a unified theory of clauses and noun phrases, ultimately helping to simplify numerous thorny issues in the syntax/morphology interface.

One of the most controversial issues in generative synstax is what properties verbal and nominal projections share and where they differ. Ogawa argues that clauses and noun phrases are perfectly parallel and tries to discern their disparities.