Electronic correlation effects play an import role in emergent phenomena such as Mott-insulator-metal transition and unconventional superconductivity. Understanding these effects present a theoretical challenge. In this talk, we will give an overview of dynamical mean-field theory (DMFT) and its combination with the local density approximation in density functional theory. Representative quantum impurity solvers including continuous-time quantum Monte Carlo method will also be discussed, together with a few measurable quantities. Finally, I will present applications of the theoretical approach to strongly correlated f-electron systems.