Few natural resource management issues have generated more controversy than decisions involving how to manage" westside" old-growth forests of the Pacific Northwest (PNW), home of the famous (or infamous, depending on one's perspective) northern spotted owl (NSO)(Strix occidentalis caurina). Yet through years of often acrimonious debate, environmental advocates, timber industry supporters, and government officials have consistently agreed on one principle: federal agencies and other owners of forestlands should base their management decisions on" sound science." Upon initial reflection, asserting that forest management decisions should rest on sound science is somewhat akin to supporting motherhood and apple pie. Would anyone suggest with a straight face that managers employ poor science? Probing this issue somewhat deeper, however, raises several important and difficult questions. If all interests support" science-based" forest management, why has it been so difficult to design and implement a strategy that enjoys broad agreement? What exactly does it mean to base management decisions on" science"? How does such a management approach also integrate legal requirements