This colloquium reviews recent theoretical and experimental progress in the nonequilibrium dynamics of isolated quantum systems, focusing on quantum quenches—sudden or slow changes in the system Hamiltonian. It discusses universal dynamics near quantum critical points, slow dynamics in gapped and gapless systems, and thermalization in closed systems. The review also covers experiments in cold atom systems and their relation to theoretical understanding. The introduction highlights how experimental advances in atomic physics, quantum optics, and nanoscience have enabled the realization of artificial systems described by models like the Hubbard and Luttinger models. These systems allow for the study of quantum dynamics, including nonequilibrium processes, which are crucial for quantum technologies. Equilibrium systems are understood through mean field theory, renormalization group, and universality, but nonequilibrium dynamics are less clear. Theoretical and experimental studies have shown that even in isolated systems, long-time dynamics can be characterized by asymptotic states. Cold atom experiments have provided insights into quantum dynamics, including the Kibble-Zurek mechanism and scaling laws for defect density. The review discusses universal dynamics near quantum critical points, where the system's response is governed by critical exponents. The Kibble-Zurek mechanism predicts defect density scaling with quench rate, and this has been confirmed in experiments. The Landau-Zener analysis provides a framework for understanding transitions between adiabatic and non-adiabatic dynamics. The review also addresses the scaling of excitations in quantum systems, showing that the density of excitations scales with the quench rate. This scaling is universal and has been verified in various models, including spin systems and bosonic models. The analysis of adiabatic susceptibilities and their scaling dimensions helps determine the behavior of systems near critical points. The effects of finite temperature on nonequilibrium dynamics are discussed, showing that thermal fluctuations influence the non-analytic contributions to heat and excitation density. The review also highlights open problems, including the extension of universality to nonequilibrium systems and the development of optimal protocols for minimizing non-adiabatic effects.This colloquium reviews recent theoretical and experimental progress in the nonequilibrium dynamics of isolated quantum systems, focusing on quantum quenches—sudden or slow changes in the system Hamiltonian. It discusses universal dynamics near quantum critical points, slow dynamics in gapped and gapless systems, and thermalization in closed systems. The review also covers experiments in cold atom systems and their relation to theoretical understanding. The introduction highlights how experimental advances in atomic physics, quantum optics, and nanoscience have enabled the realization of artificial systems described by models like the Hubbard and Luttinger models. These systems allow for the study of quantum dynamics, including nonequilibrium processes, which are crucial for quantum technologies. Equilibrium systems are understood through mean field theory, renormalization group, and universality, but nonequilibrium dynamics are less clear. Theoretical and experimental studies have shown that even in isolated systems, long-time dynamics can be characterized by asymptotic states. Cold atom experiments have provided insights into quantum dynamics, including the Kibble-Zurek mechanism and scaling laws for defect density. The review discusses universal dynamics near quantum critical points, where the system's response is governed by critical exponents. The Kibble-Zurek mechanism predicts defect density scaling with quench rate, and this has been confirmed in experiments. The Landau-Zener analysis provides a framework for understanding transitions between adiabatic and non-adiabatic dynamics. The review also addresses the scaling of excitations in quantum systems, showing that the density of excitations scales with the quench rate. This scaling is universal and has been verified in various models, including spin systems and bosonic models. The analysis of adiabatic susceptibilities and their scaling dimensions helps determine the behavior of systems near critical points. The effects of finite temperature on nonequilibrium dynamics are discussed, showing that thermal fluctuations influence the non-analytic contributions to heat and excitation density. The review also highlights open problems, including the extension of universality to nonequilibrium systems and the development of optimal protocols for minimizing non-adiabatic effects.