Do you know the difference? More than 41 million children (according to 2003 estimates from the U.S. Census Bureau) will spread out through their neighborhoods the last day of October, dressed in costumes and going door to door for candy and treats. But many Catholic kids don't know much about the two Catholic feasts immediately afterward. Do you?

Halloween, Oct. 31

A traditional secular celebration dating back to pre-Christian Celtic autumn observances, customs and superstitions. Brought to the United States in the 19th century by Irish immigrants, its name is derived from the day on which it is celebrated, All Hallows Eve, the vigil to All Saints' Day.

All Saints' Day, Nov. 1

A holy day of obligation (but not this year in the United States because it falls on a Saturday), commemorating all the blessed in heaven, and intended particularly to honor those who have no special feasts.

In the fourth century, groups of martyrs, and later other saints, were honored on a common day in various places. In 609 or 610, the Pantheon, a pagan temple in Rome that is still standing, was consecrated as a Christian church in honor of Mary and the martyrs and, later, all the saints.

In 835, Pope Gregory IV fixed Nov. 1 as the date of the observance.

All Souls' Day, Nov. 2

The annual commemoration of all the faithful departed.

The dead were prayed for from the earliest days of the Church. By the sixth century, Benedictine monasteries customarily held commemorations for departed members at Pente-cost. In 998, St. Odilio of the Abbey of Cluny fixed the day after All Saints' Day as the common commemoration of all the faithful departed. It was approved and recommended by Pope Sylvester II five years later and gradually spread throughout the Christian world, with associated customs and pious traditions, including visiting grave sites.

Source: "Encyclopedia of Catholic Devotions and Practices" (OSV, $39.95)