[BetterRed]

@ramnangel - Adding custom columns to calibre is not a 'kludge' its one of its major features. If you want to see how big a book is in terms of words and/or pages you have to add custom columns. If you want a Yes/No for Have Read/Not Read you have to add a custom column. If you read Fan Fiction you'll probably have a boatload of custom columns . . .

I do all my editing in the book list, where it's just as easy to edit a custom column as it is a standard column. Whatever can be done to Tags in the Book Details panel (what you call Preview) can be done to a similar custom column.

If you have to reinstall you won't lose anything, and providing you take regular backups (e..g daily incremental) of your libraries and calibre's configuration folder(s) then in the event of a catastrophic system failure you'll only lose books and settings added/changed since last backup.

If you wanted to create an Admin Tags/#admin_tags column you could use Bulk Edit Search and Replace to: a) copy the values starting with '_' from tags to #admin_tags, b) remove the values starting with '_' from tags.

Based on how few issues are raised about 'jackets', I suspect they are not widely used.

BR