Summary of the Extensions of the Standard Model Working Group

We summarize the results of the extended gauge group working group of the Madison-Argonne Workshop on Present and Future Colliders. Contributions are described on the previously unexamined two photon fusion production of heavy leptons, new studies of $Z'$ couplings to $\nu \bar{\nu}$ and $q\bar{q}$, and previously unexplored vector leptoquark production. More detailed accounts of these studies can be found in individual contributions.