  We examined the Wilson-Bappu effect, a relationship between the absolute
magnitude of the star, $M_V$, and the logarithm of the Ca {\sc ii} emission
width, $W_0$, over the largest $M_V$ range to date, +13 to -5, covering
M-dwarfs to type Ia supergiants. We used an extensive literature, the latest
Hipparcos reduction, data from two globular clusters, and new observations from
Apache Point Observatory to compile a sample that allowed us to study the
effect of [Fe/H] on the Wilson-Bappu relationship. Our results include
reporting the deviations from linearity and demonstrating that the Wilson-Bappu
relationship is insensitive to metallicity.
