Brief History of the Holiday
From The Dictionary of Holidays, Festivals, and Celebrations of the World by Omnigraphics Press, Inc.:
"Halloween has its ultimate origins in the ancient Celtic harvest festival, SAMHAIN, a time when people believed that the spirits of the dead roamed the earth. Irish settlers brought their Halloween customs—which included bobbing for apples and lighting jack-o’-lanterns—to America in the 1840s.
"In the United States children go from house to house in costume—often dressed as ghosts, skeletons, or vampires—on Halloween saying, 'Trick or treat!' Though for the most part the threat is in jest, the 'trick' part of the children’s cry carries the implication that if they don’t receive a treat, the children will subject that house to some kind of prank, such as marking its windows with a bar of soap or throwing eggs at it. Most receive treats in the form of candy or money. But Halloween parties and parades are popular with adults as well.
"Because nuts were a favorite means of foretelling the future on this night, All Hallows’ Eve in England became known as Nutcrack Night. Other British names for the day include Bob Apple Night, Duck (or Dookie) Apple Night, Crab Apple Night, Thump-the-door Night, and, in Wales, APPLE AND CANDLE NIGHT. In the United States it is sometimes referred to as Trick or Treat Night."
Safe Halloween Links
The National Safety Council's Halloween Safety Fact Sheet
The US Consumer Product Safety Commission's Excellent Halloween Safety Alert
Safe Halloween Tips from the Centers for Disease Control...A handy, printable PDF of SAFE HALLOWEEN tips is also available from the CDC.
E-How Video Link: How To Inspect Halloween Candy