Tagging

Tagging is storing the information about a song (title, artist, genre, etc) into the audio file. This makes the file self documenting.

A lot of media player software supports tagging.
Sometimes you might be in need of more powerful options than the standard one.

MP3Tag

MP3Tag is a popular piece of freeware.

• Write ID3v1.1-, ID3v2-, APEv2-Tags and Vorbis Comments to multiple files at once
• Full Unicode support
• Support for embedded cover art
• Automatically create playlist's
• Recursive subfolders support
• Remove parts or the entire tag of multiple files
• Rename files based on the tag information
• Import tags from filenames
• Format tags and filenames
• Replace characters or words from tags and filenames
• Regular Expressions
• Export tag information to user-defined formats (like html, rtf, csv, xml)
• Import tag information from online databases like freedb or Amazon (also by text-search)
• Import tag information from local freedb databases
• Support for ID3v2.3 (ISO-8859-1 and UTF-16) and ID3v2.4 with UTF-8

The scripting options allows you to transfer the content of one or more tags to another.

If the Band is populated, don't change it. If empty use the Artist tag

An example of renumbering the tracks (multi volume sets) can be found here.
I used the scripting options to derive opus numbers from compositions.

Saved me a lot of typing.