Thank you for the thorough feedback, everyone. Much appreciated!
After some time spent with the manual (thanks for those links, isarl), I am beginning to better understand Calibre's capabilities. But some questions remain.
1) Where do I find the Additional Restrictions in the Virtual Library? Is this setting accessed somewhere in Preferences?
2) Thanks. This issue is now resolved.
3) Is there a way to preemptively apply a search and replace command (or some equivalent command) unilaterally to a column's metadata? For example, if I wish to default the metadata in my Tags column to titlecase, can a command be set up to either modify ALL the existing metadata within a certain field (i.e. a Tags column) or to at least program the modification of ALL future imported metadata? If so, what might this particular command look? Is it possible to use a simple text command or would a regular expression be ideal? (The coding involved is still a little confusing...)
4) I have created a customized Genre column in addition to the default Tags column. Is there a way to correlate the metadata in the Tags column with the Genre column? For example, can the metadata in one field (Tags) be referenced in another field (Genre)? [If this is confusing, I have attached a screenshot to provide context.] I'm wondering if there is a more efficient process for creating the metadata infrastructure for my customized Genre column that can take its data from an existing source.
More to the point, is there a way to setup the metadata hierarchy within my customized Genre column independently of assigning the related metadata to existing books in my library?