There have been other, more detailed nature activity books and more carefully informative guides to finding nature in the city; but this easygoing Brown Paper School entry is probably more likely to win voluntary readers and, therefore, to get them growing potatoes (in pots), sprouting seeds, watching sowbugs, racing snails, making worm farms or bird feeders or backyard garbage-bin ""ponds,"" starting roof gardens, or even, if they can find a likely stream, paddling canoes made of milk cartons. (They might be less enthusiastic about making mazes for rats, especially as the only rats mentioned here are the brown and black pest varieties.) Along the way they will also find themselves reading about everything from the parts of meat animals to traveling seeds, Christmas tree farms, air inversions, and sewage treatment. None of these subjects is covered with more than passing attention, and some are treated with off-putting cuteness. (""Not everybody knows this but trees do talk."") Still, as a summer time-passer, it beats hanging out at the shopping mall.