Nuclei form the core of matter, but their description in terms of their fundamental constituents - quarks and gluons - remains elusive. The Jefferson Lab program has provided key insight into nuclear structure at extreme energy and density scales. A connection between high-density configurations and the quark structure of nuclei has raised significant questions about the modification of protons and neutrons within nuclei with potential impact on our understanding of neutron stars, neutron structure, and a range of high-energy e-A, nu-A, and A-A scattering measurements. I will summarize our current understanding based on electron scattering measurements, highlight the impact of these studies and key outstanding questions, and discuss future measurements making use of the Jefferson Lab energy upgrade and the future Electron-Ion Collider.
