Dynamical Mean-Field Theory (DMFT, Georges & Kotliar 1992) maps the Hubbard model (hopping t, on-site repulsion U) onto a self-consistent Anderson impurity problem. The local spectral function A(ω) shows a quasiparticle peak at the Fermi level (metallic) that narrows and vanishes at the Mott transition U ≈ 3W (W = bandwidth). Above U_c, the spectrum splits into lower and upper Hubbard bands separated by a Mott gap ~ U.