Chick has almost everything wrong in his story. Halloween is Celtic but not a Druid invention, and Samhain is a month, not a specific day. Jack O'Lantern was an old name for the natural static luminescense otherwise known as Saint Elmo's Fire. Pumpkins in the British Isles, before the strain was improved with American imports, were only about the size of cucumbers.
Halloween was originally a Christian observance. It was the day before All Saints' Day. In antiquity, Christians would make pilgrimages to the shrines or tombs of saints, which often was a long journey. They'd put on special clothes for this trip, and carry with them the icons or likenesses of that saint or of various saints. They'd carry a lantern of some sort (hollowing out and cutting windows in a gourd was one way of making a cheap lantern). Since they were on a holy errand, the pilgrims had the privilege or the right to stop at homes along their way and request or even demand some hospitality, such as food, and the members of the household would be blessed for their generous hospitality (or cursed if they refused).
Eventually, with the rise of cities in Europe, the shrines frequently were within the same city so long journeys were no longer necessary, but the old practice may have been preserved or morphed as a procession through the town, the icons became masks, the hospitality demanded by pilgrims turned into small delicacies, etc. After the passage of centuries, the occasion, like Christmas, devolved into being primarily for children instead of adults and a good deal of its religious significance slipped into obscurity.
Note to all you folks who are shunning Halloween because it is a Satanic Holiday---NEVER MIND!!!
Halloween was originally a Christian observance. It was the day before All Saints' Day.
Yes, but it was adapted from preexisting pagan religious customs. As I recall, the Celtic new year was on or around All Saints Day/Halloween, and it was supposed to represent the time when the doors between worlds opened up (ie, a good time to make nice with one's ancestors). In this regard it resembles Mexico's Day of the Dead, which is another example of a Christianized pagan holiday.