As we live and breathe   the challenge of our environment 

 - Washington D.C.  National Geographic Society 
 - 239p.  ill. 
<br/><br/> Includes: index 
<br/><br/><label>ISBN: </label>ISBN 87044-097-7  hb 
<br/><br/><label>Dewey Class. No.: </label>363.7