The following is an excerpt from Errol Laborde's book Mardi Gras: Chronicles of the New Orleans Carnival (Pelican Publishing). Read more of Laborde's Carnival coverage in New Orleans Magazine or at www.myneworleans.com and look for more Carnival stories from him here and on WWL-TV Channel 4.

In the final hour of carnival 2002, a rare but important ritual was enacted – and hardly anyone noticed. The ceremony was also one of carnival's briefest.

As the Rex ball was closing- after the king and queen had left their throne, and while most from the audience were either heading home or moving to the Comus ball, two men in white ties and tails approached each other from different points on the floor. The men's meeting point was in front of the box seats where both of their wives happened to be. Reaching their destination, the two stopped and stood face to face. Then something happened that caused gasps from those few left in the auditorium who happened to be watching. One of the men lifted his whistle cord from around his neck and placed it around the neck of the other. There was applause, a few cheers and lots of expressions of surprise. The Queen of Carnival, who happened to be looking back at the ball floor on her way to meet Comus, seemed tearful, happy and surprised. The man who received the whistle was her dad.

For a celebration that thrives on pageantry, one of its most important transitions happens simply. The passing of the whistle signaled a change in the captaincy of the Rex organization. Tradition has it that the identity of the Rex captain is kept secret. The reason for that, as Mark Twain once wrote in explaining the rituals of the local carnival, is not for fear of the police but for the sake of tradition itself. In the power structure of carnival, the captains are the bosses of their krewes. While the reign of monarchs lasts just for a day and their duties are strictly ceremonial, captains perform as Prime ministers concerned with the day to day governance.

While all krewes have captains, the man who wears the whistle for Rex historically takes on an extra level of importance in the guidance of the entire carnival. "It is the best civic job there is," the then outgoing captain used to say about the position he held for nearly nine years. If so, it is NOT because of the political or business gain that comes with the title. Secret jobs are hardly marketable for career advancement. Besides, the men who become captain have usually already found their place in the corporate world. Other than getting to ride a white horse and being invited to lots of debutante parties, there are few perks that come with the job.

But for those who like to mix it up with everyday issues and controversies, atop the white horse is the place to be. Whenever carnival has had crises, Rex's captains have usually been up front facing them. In 1979 when a police strike caused all parades in New Orleans to be canceled, the Rex captain of that time stood alongside Mayor Dutch Morial in defying the union organizers. During the discrimination ordinance controversy of 1991-92, a different Rex Captain stood courageously in front of the council taking the heat from both sides: some fellow captains who thought he was being too accommodating versus the ordinance's proponents who thought he was not being accommodating enough. The captain also worked behind the scenes. When the full story is known, it will show that the relatively peaceful resolution of the crisis was due largely to legal problem solving initiated by Rex leadership. One recent Rex captain served as chairman of the city's Mardi Gras Coordinating Committee having to deal with issues from the mundane: float fire extinguisher specifications, to the critical: carnival safety hazards.

Founded in 1872, the Rex organization's first captain was a newspaperman with a flair for the literary named E.C. Hancock. Even in its founding Rex was solving a problem by creating a day parade around which miscellaneous street maskers could be organized. By claiming the title of King of Carnival, the group also created a populist monarch. The fact that the new parade would be good for tourism during those tense years of Reconstruction when people were nervous about traveling was probably not lost on organizers.

As Carnival grew and other krewes were founded, Rex, by the mid twentieth century, had fallen in the shadows – still parading but without much sparkle. By the early 1960s, however, the Rex revival was in place under the leadership of the late Darwin Fenner who is credited with rebuilding the organization.

In the age of the super krewe, Rex is neither the biggest nor the richest of the parading organizations, but it is the group with the best grasp of carnival's traditions, style and elegance. As the holders of the title, "King of Carnival" Rex takes its civic responsibilities seriously.

(Among the traditions for most krewes, including Rex, is that the captaincy is an unpaid position. The significance of that became evident in the summer of 2012 when one of the super krewes faced a steep dues increase. Comparative data leaked over the Internet showed that krewe's captain's son received a six-figure salary as a director while for Rex and most others the dollar figure for salary and travel was zero.)

At the end of the 2011 Rex ball two men dressed in white ties and tails approached each other. Once more the whistle changed, as the continuity continued. I have never been one to justify Carnival's significance just in terms of economic impact– the season also creates community spirit and provides an urban identity. When Mardi Gras is measured in terms of tourism dollars, however, those who are its leaders are as civically important as the forces behind the Jazz Fest and the Convention Center, only the carnival guys wear a mask.

One also wears a whistle. When thunder is heard during carnival sometimes it's from gathering storm clouds or sometimes it is just approaching drums. While others revel, the man on the white horse has to be ready to respond to either situation.