Explore the intricacies of non-stationary quantum many-body dynamics in this second lecture delivered by Berislav Buca. Part of the "Periodically and Quasi-periodically Driven Complex Systems" program at the International Centre for Theoretical Sciences, this 59-minute talk delves into advanced concepts at the intersection of quantum physics and complex systems. Gain insights into topics such as terahertz and infrared driven quantum matter, shaken optical lattices and cold atoms, Floquet time crystals, and localization-delocalization physics in quasi-periodically driven systems. Designed for researchers and advanced students in theoretical physics, this lecture contributes to a broader discussion on the interplay between closed quantum systems, open quantum systems, and gauge theory of coupling between matter and radiation.