This book explores the interface between syntax and the other parts of the grammar, in particular phonology, morphology, and argument development. The author proceeds via a consideration of case analysis, harking back to clitics and complicated predicates (auxiliary and modal verbs) in Romance, grounding theoretical analysis in fastened exemplification. She reveals that a cautious analysis of their properties may result in a larger understanding of the interaction of the numerous parts of the grammar. The syntactic properties of clitics are thought-about in relation to their phonological and morphological attribute. The properties of auxiliary verbs are analysed from the angle of the interface between argument development and syntactic development. Modal verbs are examined on the interface between syntax and phonology. The analyses of clitics and auxiliaries throw fascinating new light on the hyperlink between Romanian and Balkan/Slavic. This is usually a helpful contribution to the analysis of grammatical interfaces and to Romance verbal typology and comparative linguistics.