Abstract: An analytic description of low-energy properties of four-dimensional gauge theories such as QCD remains a long-standing open problem. A fruitful strategy in the past three decades has been to take one of the spatial directions to be a circle; this leads to a decomposition of the 4D theory into finitely many simpler 3D effective theories at low energies. While analytically understanding these 3D building blocks is generally out of reach, a systematic description is beginning to emerge when the parent 4D theory possesses supersymmetry. In this seminar, recent results along these lines will be explained, focusing on perturbative effects in chiral supersymmetric gauge theories. The talk is designed to be pedagogical and will begin with a review of the necessary background on supersymmetric gauge theory