Galaxies are observed to obey a strict set of dynamical scaling relations. We review these relations for rotationally supported disk galaxies spanning many decades in mass, surface brightness, and gas content. The behavior of these widely varied systems can be summarized with a handful of empirical laws connected by a common acceleration scale.
Keywords: galaxies: dwarf; galaxies: irregular; galaxies: kinematics and dynamics; galaxies: spiral; galaxies: structure.