  I use photometry and spectroscopy data for 24 Type II plateau supernovae to
examine their observed and physical properties. This dataset shows that these
objects encompass a wide range in their observed properties (plateau
luminosities, tail luminosities, and expansion velocities) and their physical
parameters (explosion energies, ejected masses, initial radii, and 56Ni
yields). Several regularities emerge within this diversity, which reveal (1) a
continuum in the properties of Type II plateau supernovae, (2) a one parameter
family (at least to first order), (3) evidence that stellar mass plays a
central role in the physics of core collapse and the fate of massive stars.
