This volume is a collection of invited papers on the theory of groups, most of which were presented at the biennial Ohio State-Denison Conference, May 1992, in memory of Hans Zassenhaus. These papers treat important topics in the theory of p-groups, solvable groups, finitely presented groups, arithmetic groups, monodromy groups and the general structure and representation theory of groups. Of particular note are papers by John Walter on root systems, by Leonard Scott on integral equivalence of permutation representations and Alex Turull on generalized Brauer groups.