内容摘要：The origin of mass is a most profound puzzle in physics. In this talk, I first discuss the origin of mass from the 4d Higgs mechanism in the Standard Model (SM), with particular emphasis on the mass generation of light neutrinos (as introduced by Pauli) and its connection to the right-handed neutrinos that constitute the last missing piece of the SM, as well as their cosmological non-Gaussian signatures from inflation. I will then discuss topological mass generation of the 3d Chern-Simons gauge and gravity theories. Unlike the Higgs mechanism, topological mass generation does not have a clear interpretation at the Lagrangian level. However, I will demonstrate that the Topological Equivalence Theorems for gauge bosons and for gravitons provide a conceptual and quantitative formulation of the topological mass generation at the S-matrix level. I will further discuss geometric mass generation in Kaluza-Klein (KK) gauge and gravity theories and in string theories. Building on these, I will highlight a truly profound relation, (Gravity) = (Gauge Theory) ² , and demonstrate its massive realizations, which provide fundamental clues to the deep gauge-gravity connection and their unification.