Dynamics of open quantum systems is one of the most challenging topics in physics, chemistry, and biology. The environment-induced quantum dissipation and decoherence dynamics and its control has become a key task for practical implementations of nanoscale solid-state quantum information processing. The study of non-Markovian decoherence dynamics of open quantum systems and reservoir engineering has received considerable attention due to the rapid development of quantum technologies in the field of ultrafast photonics, ultracold atomic physics, nanoscience, quantum transport in electronic nanostructures, quantum chemistry and solid state mesoscopic physics. I will mainly discuss on the dynamics of various open quantum systems using an exact master equation approach which is closely related to the nonequilibrium Green’s function technique in manybody quantum physics. I will also discuss about my current research problems and progress as a consequence of these studies.