This course aims at establishing solid foundations in condensed matter physics. Prior to take this class, students should be familiar with basic electronic properties of materials (such as MSE225) and standard applied mechanics (such as MSE227). Starting with the band theory of solids and tight-binding model, it covers the semiclassical theory of metals, and addresses the concepts and Bloch states, Fermi surface and quantum oscillations, as well as scattering rates, beyond the relaxation time approximation. Then, electron liquid theory is addressed and basics concepts related to electron-electron interactions are covered, including the Stoner criterion, the Hartree-Fock approximation, Fermi and Luttinger liquids, and charge/spin density waves. Finally, superconductors are considered, including London, Ginzburg-Landau and BCS theories.