According to one craft book All Hallow Eve is a celebration that dates all the way back to pre-Christianity, to the ancient Celts and the Druids. Originally on the eve of November harvest time was celebrated, whereas 1st May sowing was the theme. Then there was the solstice in June and the ripening was the new party theme.
Once Christianity overtook this earlier religion, elements of these old traditions remained, but took on new forms. In other words the party continued it was just called something else — All Hallow Eve or All Saints Day.
All Hallow Eve is now associated with carved pumpkin faces, dressing up as scary monsters and Star Wars characters (LOL), and deliciously terrifying ghost stories. My, the more things change, the more they really stay the same.