Dr. Robert T. Lackey, Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon, presents a paper at the VII International Congress of Ecology, Florence, Italy, on 19-25 July 1998.  Ecosystem management is a magnet for controversy, in part because some of its formulations rest on questionable assertions that are radically contested. These assertions are essential to understanding much of the conflict surrounding ecosystem management and, therefore, deserve thoughtful discussion and vigorous debate. Unfortunately, the ideas usually receive little scrutiny because critics, supporters, and the public are, understandably, absorbed in the personal and societal consequences of implementing controversial public policy choices under the rubric of ecosystem management.