Batch MP3 Tag Editor for mac

Hi,
Is there a good tag editor (other than the native music app), that works with batches of Mp3 files? For instance, I have one folder which contains 20 files by the same artist from the same album, with different titles. Is there a way to batch edit them without having to open each one? Even if I can open them all together, then edit each one, adding the appropriate info, that's fine. I'm just wondering what people use to accomplish the task of tag editing.