I am an utter newbie to SRU and would be very grateful for your help. I am trying to implement an application in which the user (a) first scans an ISBN from a book, then (b) does a lookup via SRU to get information from the Library of Congress (and thereby avoid manual entry). I am using (for example) http://z3950.loc.gov<http://z3950.loc.gov>:7090/voyager?version=1.1&operation=searchRetrieve&query=isbn=9781449313944 and I am getting back: numberOfRecords: 0 diagnostic: message: Unsupported index detail: isbn However, if I get the Explain record, it says <index id=“7”> <title>isbn</title> <map><name set=“bath”>isbn</name></map> </index> So I would have thought that what I attempted to do was legal.  What am I missing here?  How can I do an ISBN lookup? Thank you for your help. Cheers, Rick Aurbach Aurbach & Associates, Inc.