  We present a measurement of the rate of gluon splitting into bottom quarks,
$g \to b\bar{b}$, in hadronic $Z^0$ decays collected by SLD from 1996 to 1998.
The analysis was performed by looking for secondary bottom production in 4-jet
events of any primary flavor. A topological vertex mass technique was used to
tag the two jets with the smallest angle between them as $b/\bar{b}$. We
obtained a rate of $g \to b\bar{b}$ per hadronic event to be $(3.07 \pm 0.71
{\rm (stat.)} \pm 0.66 {\rm (syst.)})\times 10^{-3}$ (preliminary).
