@nikoski,
The most powerful Tag and Genre management tool in Calibre can be found at
https://www.mobileread.com/forums/sho...d.php?t=247425.
See the thumbnails attached below to give you a grasp of its capabilities.
DDC is the Dewey Decimal Code and LCC is the Library of Congress Code. The Tags are in "structured English", which is in the spirit of BISAC subjects, meaning that the most general words are to the left, and the most specific to the right.
Example: Factual:History:Wars&Military-WWII-Africa-Northern Africa-Libya.
DaltonST