[Adoby]

Calibre has a "Create Catalog" feature. It can do exactly what you want.

If you don't see the button for "Create Catalog" you can go to settings and add it to the main menu.

You might want to consider using a custom field of the type tags. It provides some very nice extra functionality in the tag browser.

For instance you get a category editor you can access by right-clicking the field in the tag browser.

And you can also use hierarchical tags by specifying that under Look And Feel and then Tag Browser.

Or you can use several tags for the same book. And search and create virtual libraries based on various combinations.

Hierarchical:
Nonfiction.Business.Marketing
Nonfiction.Business.Marketing.Internet

Multiple tags:
Business, Marketing, Nonfiction