Trick-or-treating wasn't widely popular in the United States until around 1940, writes Nicholas Roger, author of "Halloween: From Pagan Ritual to Party Night." Before then, the mischievous holiday had spiraled into an adolescent free-for-all, marked by rampant vandalism and excessive tomfoolery. As communities sought to provide alternative Halloween activities for the local youth at the turn of the century, trick-or-treating as we know it today caught on. Retailers also noticed the trend and began offering readymade costumes, and candy manufacturers seized on the golden opportunity.
Sensational reports of razors in candy apples, treats laced with laxatives and other horror stories dealt a blow to trick-or-treating in the 1970s and early 1980s. Nevertheless, the tradition is still alive and well today -- just ask the National Confectioners Association. The pumpkin-hued holiday takes the cake for the highest candy sales, with Americans shelling out more than $2.2 billion on sweets in 2008. But in spite of Halloween's commercial appeal, those ancient Celtic rites echo on as hordes of costumed children trick-or-treat every year in the crisp October air.