Scaling laws in disk galaxies
  A brief overview of several recent disk galaxy scaling relations is
presented, along with some historical background. In particular, after
introducing the (basic) radial light profiles of disk galaxies, I explain
several important `structural' scaling relations and review the latest
bulge-(black hole mass) diagrams. I go on to present the typical bulge-to-disk
flux ratios of disk galaxies and suggest the use of a grid of bulge-to-disk
flux ratio versus disk Hubble type - based on the nature of the spiral arms -
to complement the Hubble-Jeans sequence. I then briefly mention pure disk
galaxies before cautioning on difficulties with identifying pseudo-bulges built
from secular evolution. Finally, I conclude by discussing a likely connection
between modern day bulges in disk galaxies and high-redshift (z ~ 2+/-0.5)
compact galaxies which may have since acquired a disk via cold flows and
quiescent accretion.
