  Type Ia Supernovae are in many aspects still enigmatic objects. Recent years
have witnessed a bonanza of supernova observations. The increased samples from
dedicated searches have allowed the statistical investigation of Type Ia
Supernovae as a class. The observational data on Type Ia Supernovae are very
rich, and the uniform picture of a decade ago has been replaced by several
correlations which connect the maximum luminosity with light curve shape, color
evolution, spectral appearance, and host galaxy morphology. These correlations
hold across almost the complete spectrum of Type Ia Supernovae, with a number
of notable exceptions. After 150 days past maximum, however, all observed
objects show the same decline rate and spectrum. Bolometric light curves are a
handy tool to investigate the overall appearance of Type Ia Supernovae. The
nickel masses derived this way show large variations, which combined with the
dynamics from line widths, indicate that the brighter events are also coming
from more massive objects. The lack of accurate distances and the uncertainty
in the correction for absorption are hampering further progress. Improvements
in these areas are vital for the detailed comparison of luminosities and the
determination of nickel masses.
