Discriminating between Higgs Boson models using $e^+e^-\to t \anti t \h$ and $Z\h$ at the NLC

We demonstrate that the process $e^+e^-\to t\anti t h$ at the NLC provides a powerful tool for extracting the $t\anti t$ (Yukawa) couplings of the $\h$. In combination with the $\epem\to Z\h$ process, an accurate determination of the $ZZ$ coupling of the $\h$ is also possible. The resulting ability to distinguish different models of the Higgs sector is illustrated by detailed studies for two-Higgs-doublet models.