The papers in this volume address a range of issues and problems in current phonological theory, examining many levels of phonological representation. The papers grew out of a conference held in May, 1991, at the University of Illinois at Urbana-Champaign, in celebration of the twenty-fifth anniversary of the Department of Linguistics. The goal of the conference was to provide a forum for the discussion of some of the leading ideas and innovations in phonology today. Over one hundred researchers and students participated in presentations and lively debate. The conference imposed no single theme under which all of the papers were organised.