Walter V. Reid is Vice President for Program at World Resources Institute.

Kenton R. Miller is Director of WRI\'s Program in Biological Resources and Institutions.

We are grateful to Mohamed El-Ashry, Nate Flesness, Tom Fox, Vernon Heywood, Dan Janzen, Nels Johnson, Jeffrey McNeely, Gordon Orians, Peter Raven, Ulysses Seal, Dan Simberloff, Michael Soulé, Mark Trexler, and Geerat Vermeij for their valuable comments on all or part of the draft report. Special thanks to Dee Boersma, Kai Lee, Jeffrey McNeely, Gordon Orians, and robert Paine for many invaluable discussions on ecology, conservation, and development.