In this volume, the authors discuss what practical contributions ecology can and can’t make in applied science and environmental problem solving. In the first section, they discuss conceptual problems that have often prevented the formulation and evaluation of powerful, precise, general theories, explain why island biogeography is still beset with controversy and examine the ways that science is value laden. In the second section, they describe how ecology can give us specific answers to practical environmental questions posed in individual case studies, and argue for a new way to look at scientific error. A case study using the Florida panther is examined in the light of these findings.