This respectable but thinly spread companion to the PBS TV-series combines focused nature appreciation (in sidebar reports on particular, illustrative species) with environmental overviews of ten ecosystems--forests, mountains, wetlands, oceans, and so on. It's a big order, and Wallace fills it conscientiously. Yet however readable his prose, the uncontroversial, unaccented, textbookish inclusiveness can be numbing. Thus a chapter on grasslands moves within a few pages from the black-footed ferret, to homo erectus, to the American pioneers, then back to the ferret; another on the polar regions applies the same lecture-series tone to the red knot shorebird, the Antarctic krill, and the Native Claims Settlement controversy; and the desert chapter skims over a range of topics from water for Tuscon to endangered species of cactus. Each chapter also contains examples of human depredation, but ends on a note of hope; for the project's stated aim is to make readers aware of environmental interconnection, arouse concern for endangered life forms, and convince people that conservationist efforts can make a difference. What Wallace does not offer is any new information, thought-provoking observation, political analysis, or activist direction. Still, this systematic once-over might be just the environmental survey course TV viewers want. And that audience will find the distance from screen to text attractively bridged by the book's crisp page design and numerous color photos.