QCD and Nuclear Theory at the Electron-Ion Collider*

QCD has been very successful in describing the short-distance dynamics owing to its defining property - "Asymptotic Freedom". QCD's another defining property, "Confinement", makes the Theory and its emergent phenomena extremely rich at the fermi scale, opening up a new femto-science. The Electron-Ion Collider, which US Department of Energy recently approved for construction at Brookhaven National Lab, is sitting at a sweet spot for rich QCD dynamics, capable of taking us to the next frontier of Nuclear Science! In this talk, I will demonstrate that the EIC will be an ultimate QCD machine, capable of discovering and exploring the emergent phenomena of QCD and the role of color and glue at the fermi scale, and a unique and necessary facility for the "tomography" of nucleons and nuclei with unprecedented sub-femtometer resolution to help explore their internal structure and landscape in terms of quarks and gluons, which allows us to address the most compelling unanswered questions about nucleon and nuclei - the elementary building blocks of our visible world.