Lisa Bitel, professor of religion and member of the Interdisciplinary Research Group, appeared on this History Channel TV special, talking about the Celtic roots of the holiday.
Description from History Channel:
Halloween began centuries ago as a pagan holiday that honored the dead that warned of a netherworld of spirits and ghosts. Today, Halloween has morphed into a day for breaking rules, pushing boundaries and wearing disguises. But Halloween remains a time for us to deal with our own mortality. Our modern Halloween traditions have ancient roots – people were going door to door and begging for treats on Halloween night as far back as the Middle Ages.
We may think our Halloweens are crazy, but Halloweens past have been wilder and more dangerous than they are now. During the depression, Halloween became so violent and destructive that civil authorities had to step in and prevent wide-spread vandalism in cities across America. Their solution, the ritual of “trick or treat,” now generates $2 billion dollars in candy sales each season. And these days adults get dressed up for the holiday almost as much as kids do. But no matter how many jack-o-lanterns get carved or kids yell “trick-or-treat!” Halloween is still all about the “scare.” Two thousand years and counting, and we still like to be scared on the night of October 31.
The special is available for purchase on DVD from History Channel.