6.  Acknowledgments

      We are grateful to all those who have tried learn, for we have benefited greatly from their suggestions and criticisms. In particular, M. E. Bittrich, J. L. Blue, S. I. Feldman, P. A. Fox, and M. J. McAlpin have provided substantial feedback. Conversations with E. Z. Rothkopf also provided many of the ideas in the system. We are also indebted to Don Jackowski for serving as a guinea pig for the second version, and to Tom Plum for his efforts to improve the C script. $LIST$