Explore the intricacies of Heavy Quark Effective Theory (HQET) and Soft-Collinear Effective Theory (SCET) in this advanced lecture, part of the School for Advanced Topics in Particle Physics (SATPP) series on Selected Topics in Effective Field Theories. Delve into the systematic approaches for describing physics at different scales using relevant degrees of freedom, essential for understanding the universe from TeV scales to meson and baryon observables. Gain valuable insights from expert lecturer Matthias Neubert in this 75-minute session, designed for postdoctoral fellows and advanced PhD students in theoretical particle physics with a strong background in quantum field theory and the Standard Model.