The final chapter of the book, Chapter 6, is a summary of the main findings. Here I review the main conclusions I have reached through the book and point to the main directions for further research. The chapter is divided into two main sections. Section 6.2, Major findings of the book, reviews the major descriptive generalizations illustrated in this book, such as the existence of two types of prepositional phrases in Spanish nominal expressions according to their movement possibilities; and the main theories the book has provided evidence for, such as the proposal that ellipsis processes belong to the PF component. Section 6.3, Further Research, discusses some of the directions that need to be explored to expand the analysis of this book. For instance, this section makes explicit the need of more research from a comparative perspective that can help us to determine the plausibility of the analysis described.