Given the explain record at the other end of the following URL, how  
do I query the Library of Congress for an ISBN number:

For example, I see the following in the explain output but I don't  
know how to turn that into a query:

   <index id="7">
     <map><name set="bath">isbn</name></map>

Something like this returns an "Unsupported index" error: 

Eric "Feeling Embarrassed" Morgan
University Libraries of Notre Dame

(574) 631-8604