The roots of this book and its sister volume, Mammal Phylogeny: Placentals, go back to discussions and plans, shelved for a while, between F. S. Szalay and W. P. Luckett during the international and multidisciplinary symposium on rodent evolution sponsored by NATO, July 2-6, 1984, in Paris. That conference, orga- nized by W. P. Luckett and J. -L. Hartenberger, the proceedings of which were published in 1985, proved an inspiring experience to all of the participants, as this was repeatedly expressed both during and after the meetings. In addition to issues relating to rodents, general theoretical topics pertaining to the evolutionary biol- ogy and systematics of other groups of mammals regularly surfaced during the presentations and discussions. M. J. Novacek, who was also a participant in the rodent symposium, shared with Luckett and Szalay the enthusiasm acquired there, and he also expressed strong interest for a meeting on mammal evolution with a general focus similar to that of the rodent gathering. In 1988, Szalay and Luckett, after having planned in detail a program, direc- tion, and core list of participants, were awarded a $30,000 grant by the Alfred P. Sloan Foundation through the Research Foundation of the City University of New York. The grant was contingent upon obtaining additional funds sufficient to assure that the symposium would be held. Raising the remaining funds proved to be a problem.