The study of the functional structure of the clause has changed the theoretical and descriptive study of natural language syntax. The lexical verb looked like a plausible candidate for the head of the sentence, but clearly the sentence potentially contained more material than a single X-bar schema could integrate. The V-to-I movement operation is not a formal trick to align syntax and morphology: it predicts that certain changes in word order should be produced by the movement of the verbal root. The close connection between syntax and morphology is confirmed by other cases of microcomparison. One domain which has been extensively investigated in this connection is the comparison between Icelandic and the Continental Scandinavian languages. The structural maps of the different zones of the clause have provided a model for pursuing on a large scale and on a fully systematic basis the project of a detailed cartography of syntactic structures.