Hughes -- an intriguing, personal guide to the Amazon -- interweaves anecdote, ethnography, the history of exploration, conservation and biology in this engaging overview of the region. He focuses on a small Brazilian riverine community and the transformation of their river over the last 50 years. Make no mistake, this is an academic book chock full of theory but an uncommonly artful, absorbing one. Hughes is a professor of anthropology at the University of California at Santa Cruz.  (AMZ85, $33.95)