Beckerman, an Oxford economist, takes on three phrases frequently invoked in debates over environmental policy: "sustainable development," "the precautionary principle," and "intergenerational equity." He demonstrates that each is highly problematic -- and that some interpretations of them could have detrimental effects on the world's poor and on future generations. Beckerman finds clear thinking and clear expression deficient in most public debate (even among those who know better), and his discussion of climate change and biodiversity has resonance well beyond those two illustrations. The notion of "sustainable development," for example, rests on two erroneous assumptions, according to Beckerman. First, he finds the claim that continuing growth will ultimately exhaust the world's resources (and therefore stifle future growth) deeply flawed, both empirically and conceptually; future generations are in fact likely to be much better off. Second, he disputes the term's claim to the moral high ground, based on a view of intergenerational equity that cannot, Beckerman argues, withstand scrutiny. Serious debate about current actions (or inactions) with long-term effects must take into account Beckerman's cogent arguments.