Conservationist DiSilvestro ( The Endan gered Kingdom: The Struggle To Save America's Wildlife, LJ 5/15/89) builds a carefully argued case for shifting from a public-lands policy of protecting remnant wild fragments and endangered species in response to crisis situations to managing for biodiversity in the first place. The present system makes preserving biodiversity impossible because it ignores ecosystem integrity and gives privileges to commercial interests. DiSilvestro argues for a new approach employing a technique called gap analysis to identify ``unprotected species or wild communities by indirect evidence of plant life.'' Species diversity can then be maintained by constructing ecological corridors connecting isolated wild places. DiSilvestro outlines the federal legislation required to carry out this program and the enhanced scientific curriculum necessary to ensure its long-term support. Essential for school and academic libraries and all but the smallest public libraries.-- Joan Elbers, Montgomery Coll., Rockville, Md.