Explore the dynamics of 2+1-dimensional quantum field theory in this advanced lecture by Nathan Seiberg, part of the Kavli Asian Winter School on Strings, Particles and Cosmology 2018. Delve into recent advances in the field, with a focus on the role of symmetries, topology, and duality. Examine key concepts such as particle on S, coupled systems, and 2d CpN-1 models. Investigate physical interpretations, first-order transitions, and U(1) Chern-Simons theory in 3D. Gain insights into complex topics like non-spin kE zZ and trivial contact functions. Conclude with a Q&A session to deepen understanding of these cutting-edge concepts in theoretical physics.