This monograph is structured as a collection of clinical case studies all addressing the relationship between lexicon and morphosyntax. It shows that various less-studied aphasic syndromes – including Logopenic Primary Progressive Aphasia, Mixed Trascortical Aphasia, and Crossed Aphasia – and not only ‘classic’ Broca’s Aphasia can enhance findings worthy of consideration in contemporary theoretical debates on the status of traditional categories, and particularly on the lexical/functional divide in grammar. The rationale of this study is precisely to build a bridge between experimental evidence from clinical linguistics and theoretical arguments from morpho-syntactic analysis. Furthermore, this book addresses the recent resurgence of interest within neuropsychology in single case studies, which can be crucial in order to corroborate (or falsify) theoretical advancements in linguistics.