Galactic disks exhibit a wealth of dynamical features, such as bars and spiral arms, that are thought to play a prominent role in regulating how a galaxy evolves over time.  Where conventional theories offer only a limited picture of how these structures originate, we have developed a more general description that makes testable predictions for direct comparison to observations.  This will be especially relevant for understanding the early presence of bars and spirals in galactic disks discovered with JWST’s new view further back in cosmic time, and for quantifying the impact these features can have on their host galaxies.