  The beam energy spread is a major issue in future attempts to study the
$t\overline{t}$ threshold at $e^+e^-$ colliders. Muon colliders are expected to
naturally have narrow band beams making them an ideal place to study the
excitation curve. We present the parameter determinations that are possible
from measuring the total cross section near threshold at a $\mu ^+\mu ^-$
collider.
