The Metadata? Or the Content of the books?
I ask, because the
TAG BROWSER is the metadata indexed.
OTOH, standard rules still apply
GIGO
Calibre provides a number of tools to help you house keep metadata.
In the Tag Browser: Manage. This allows you to adjust from that perspective. Fixing there,
makes all uses follow (Change once, affects many. The reason a Relational DB is so great)
While an entry is in Edit mode: right click: there is a menu of built in quick adjustments. My fav: Change case
)