In ancient times, Halloween costumes held serious supernatural connotations. The holiday originated 2,000 years ago in Ireland and the United Kingdom with the Celtic festival of Samhain. Samhain was a celebration that took place on November 1, and marked the end of the autumn harvest and the beginning of the New Year.

The Celts believed that on October 31, the night before the New Year, the boundary between the living and the dead became blurred and ghosts returned to earth. When people left their home, they put on masks or disguises so that the evil spirits would not recognize them and cause them harm. Thus the tradition of dressing up in costumes on Halloween was born.

The modern day Halloween practice of going trick-or-treating emerged in the 1800s, when Christianity spread to the Celtic lands. During this time period, the Church, which disapproved of some of the holiday's prior rituals, renamed November 1 All Saints' Day and designated it as a time to honor saints and martyrs.

The pope also instated a new holiday on November 2 called All Souls' Day. On this day, the poor would venture from house to house and solicit "soul cakes," a type of pastry, in return for promising to pray for families' dead relatives. This process was referred to as "going-a-souling," and is the basis for the modern day custom of going trick-or-treating.

While Halloween first originated overseas, it became popular in the United States during the second half of the 19th century, when the country received an influx of European immigrants, many of them fleeing Ireland during the potato famine in 1846. While some pagan aspects of the holiday did translate to American culture, by the late-1800s Halloween had evolved into a holiday designed for social interaction rather than divine intervention.

Today, the commercial industry capitalizes on the original mysticism surrounding the holiday by promoting the sale of costumes and decorations reflecting its pagan nature, but these costumes and decorations have greatly evolved over time.

While it is inevitable that any large Halloween gathering today will include at least one witch or ghost, today's costumes now embody many pop culture figures not necessarily pertaining to the supernatural. Many women don blonde wigs, red lipstick and white halter-top dresses to portray Marilyn Monroe as she appeared in the movie The Seven Year Itch, and a popular costume choice for guys includes tightie-whities, a white button-down shirt, white socks and Ray-Ban shades to portray Tom Cruise in the movie Risky Business.

In more recent developments, many girls have dressed up as precocious pregnant teenagers to portray Juno MacGuff, in the 2007 movie Juno, while countless males have worn purple suits and garish makeup to portray the late Heath Ledger in his last role as the Joker in The Dark Knight.

Dressing up as recently-deceased celebrities will no doubt be popular again this year, and an article in Money magazine entitled "Top 2009 Halloween Costumes: Dead Celebrities" predicts that Michael Jackson will no doubt be one of the most popular costume choices this coming holiday. The article also states that other possible dead celebrity costume options are Farrah Fawcett, Ed McMahon and infomercial pitchman Billy Mays.

While costumes have become more recent, they have also become more controversial. Many costumes nowadays are inherently--if not intentionally-- racist. A New York Times article published last week described an ongoing argument that began when companies such as Target and Walgreens debuted their "illegal alien" costume option in stores. The costume consists of a rubber alien mask and orange jumpsuit, with the words "illegal alien" emblazoned across the front.

According to the article, the costume is "reigniting debate over a long-used term based on the U.S. government's designation of all foreigners as aliens," and currently "has immigration advocates calling upon retailers to pull the costume from its shelves."

Another perhaps equally troubling phenomenon that has emerged in recent years is not the type of clothing children and teenagers are wearing, but the lack thereof. Halloween has become an excuse for teenage girls to dress in revealing ways that would be deemed inappropriate by everyday standards. Packages in the women's costume section in iParty advertise anti-feminist "medieval wench" costumes complete with low-cut corset tops alongside "sexy nurse" outfits with short skirts and thigh-high tights.

However, "the hardcore girls just wear lingerie and some form of animal ears," Cady, in Mean Girls, says.

Taking into account the pagan nature of the holiday, controversy is to be expected. The source of controversy has merely evolved over the years from topics like spiritualism to sexism. In his book Halloween: From Pagan Ritual to Party Night, Nicholas Rogers defends the holiday, saying that although "Halloween at the millennium is contested and in many respects a controversial holiday...Halloween still maintains some vestigial links to the harvest." Pumpkins and apples remind people of aspects of the holiday that originated to celebrate the harvest, and Rogers says that many people still believe that dressing up in Halloween costumes "allows children the opportunity to be fanciful, to indulge their imaginations in a familiar setting, and perhaps to come to terms with the sinister in warm and familiar surroundings."