Galaxies can be described in terms of their structure, dynamics and stellar populations.  Some very robust correlations between various galaxy structural properties, such as total luminosity, maximum circular velocity, and size show rather small scatter, hinting at well-regulated galaxy formation processes.  A major challenge to understanding these
scaling relations, and ultimately galaxy formation and evolution, is the elusive interplay between visible and dark matter.  I will discuss the latest derivations of galaxy scaling relations and their link with
modern cosmological models.