During the last few decades, our understanding of the Trans-Neptunian region of the Solar System has been revolutionized due to new discoveries and theoretical advances emerging from massive numerical simulations. I will review the main items of this development and identify some remaining open issues. A research project aiming to clarify or resolve these issues will be presented. Examples of features to be discussed include the scattered disk, the sednoids, the Oort Cloud and the purported Planet Nine.