I communicated this issue to the list a while ago. In case anyone has the same problem, I have solved this the following way: Go to system preferences Cataloging NoZebraIndexes Change isbn to nb save Reindex using rebuild_nozebra.pl Now ISBN searches work. I still have the same problem with "Limit type to" What is the type index called in NoZebraIndexes? I will appreciate comments about this issue. 1) Why is this? 2) How does zebra = yes handle isbn searches?