I want to ask a detailed question about recommendations for cataloging one's library of magic books (on computer). Which forum would be appropriate? I've gone through the whole Index but not identified an appropriate one there.

The closest forum we have is the "where to put it all" which is basically for prop management however since you have the books and are looking to catalogue them, it could be considered prop management.

Might I recommend collectorz.com I use their music cataloging software and am quite pleased.