9 years with no Calibre Contender? Impressive!
Just for the record, there are some Open Source solutions to organize big ebook libraries
- Library Simplified ( SimplyE ) -
www.librarysimplified.org
Apache licence - by Library E-Content Access Project (LEAP) [The New York Public Library / Institute of Museum and Library Services / Digital Public Library of America (DPLA) ]
- Invenio -
http://invenio-software.org
MIT licence - by CERN
- Open Monograph Press -
https://pkp.sfu.ca/omp/
GPL v2 licence - by PKP Public Knowledge Project
Note: Even if not using Calibre server, Calibre can be useful for tasks as file names, metadata, quality checking and some book clean up before sending the books to other systems!