  We present a study of the type IIn supernova (SN) 2005gl, in the relatively
nearby (d~66 Mpc) galaxy NGC 266. Photometry and spectroscopy of the SN
indicate it is a typical member of its class. Pre-explosion Hubble Space
Telescope (HST) imaging of the location of the SN, along with a precise
localization of this event using the Laser-Guide-Star assisted Adaptive Optics
(LGS-AO) system at Keck Observatory, are combined to identify a luminous
(M_V=-10.3) point source as the possible progenitor of SN 2005gl. If the source
is indeed a single star, it was likely a member of the class of luminous blue
variable stars (LBVs). This finding leads us to consider the possible general
association of SNe IIn with LBV progenitors. We find this is indeed supported
by observations of other SNe, and the known properties of LBV stars. For
example, we argue that should the prototypical Galactic LBV eta Carina explode
in a phase similar to its current state, it will likely produce a type IIn SN.
We discuss our findings in the context of current ideas about the evolution of
massive stars, and review the census of SNe with identified progenitors. We
introduce the concept of the progenitor-SN map as a convenient means to discuss
the present status and future prospects of direct searches for SN progenitors.
We conclude that this field has matured considerably in recent years, and the
transition from anecdotal information about rare single events to robust
associations of progenitor classes with specific SN types has already begun.
