This is a collection of articles describing and analyzing several of the most important morphosyntactic features for which the formal comparison between Basque and its surrounding Romance languages is relevant, such as word order, inflection, case, argument structure and causatives. In the context of a language virtually all of whose speakers are bilingual in either Spanish or French, the theoretically informed in-depth description offered in this volume focuses on the fine grain of linguistic structures from languages typologically quite apart but coexisting and probably interacting in the minds of speakers. It therefore aims at shedding some light on the types of interactions between different systems and on the systems themselves.