If you don't want to use Terminal, you can also download pdurrant's
ePub Zip/Unzip AppleScript applet from here:
https://www.mobileread.com/forums/sh...ad.php?t=55681
Put the applet on your desktop then drag your epub onto the applet and it will unzip it for you.
You can also drag an unzipped epub folder onto the applet to re-zip it up into an epub again.