Reverberation Mapping and Implications for Narrow-Line Seyfert 1 Galaxies

Reverberation mapping is the principal method for determining the masses of the central black holes that power AGNs. I will discuss recent reverberation mapping results in the context of how these affect our understanding of narrow-line Seyfert 1 galaxies. I will argue that NLS1s are,for the most part, the low-luminosity extremes of a class of objects that should be defined by accretion rate rather than simply by line width.