With jacket arms that reached the fingertips and pants worn tight at the waist, bulging at the knees and choked at the ankles, it was nearly impossible to ignore a man wearing a zoot suit.

Accessorized with a key chain that extended to the knees and a fedora-like hat with a feather attached, the fashion certainly said something about those who sported it. But what statement were those who were donning the look in the late 1930s and early 1940s trying to make?

That’s one of questions Kathy Peiss explores in her new book, “Zoot Suit: The Enigmatic Career of an Extreme Style.” In the book, Peiss, the Roy F. and Jeannette P. Nichols Professor of American History in Penn’s School of Arts and Sciences, examines the fashion phenomenon that became so politically polarizing it played a part in sparking a vicious uprising in California, known as the Zoot Suit Riots.

“I argue that people [wore] it for a whole range of reasons,” she says. “It had many different meanings, including the pleasure of looking sharp and being part of a group of young people in the war years. The zoot suit should not be looked at solely as a costume that conveys political resistance.”

Peiss traces the creation of the zoot suit to Harlem in the mid to late 1930s, when tailors began making them out of wool or colorful varieties of rayon. Although its exact origin is unknown, the term “zoot suit” appears to have come from the rhyming slang, or jive, spoken in the African-American community at the time, Peiss says.

“They were generally worn by young men of African-American descent, initially,” Peiss says. “Mexican-American and white working-class men also would wear them. Typically they would buy them at local clothing shops and have them tailored to this oversized style.”

The suit’s rise in popularity coincided with the emergence of the jitterbug and other forms of swing dance music. The flowing look of the suit was particularly flashy on the dance floor, and young people took note. Their parents, however, were not quite as smitten by the style.

“Initially it was mainly a mystery to mainstream Americans,” Peiss says. “It was seen as strange but not necessarily sinister. Over time there [was] a perception that the zoot suit is unpatriotic.”

At the dawn of World War II, the zoot suit was condemned by the U.S. government as wasteful. Not surprisingly, the criticism did little to dissuade its fans from wearing it, and in fact may have even attracted more people to the look. In the early 1940s, working-class youth, entertainers and dancers continued to wear zoot suits, and the look spread to Italian Americans, Jews, and even some teenage girls.

“In the midst of the war it is associated with men who are criminals or members of gangs,” Peiss explains. “Around 1943, there is a riot that breaks out in Los Angeles. White servicemen and civilians begin to attack young men, especially Mexican-American men. They rip the clothing off their bodies, and the zoot suit takes on this sense of being a danger.”

In her book, Peiss writes that during the Zoot Suit Riots, “a band of 50 sailors armed themselves with makeshift weapons, left their naval base and coursed into downtown Los Angeles in search of young Mexican Americans in zoot suits.” The sailors viciously beat the zoot suiters, and the next day even more servicemen “hired a convoy of taxicabs to go into to East Los Angeles, where they accosted pachucos [Mexican Americans] on the street and even pushed their way into private homes.”

“On the one hand it may seem like a trivial style, but what I would say is that we have a tendency to read style for its political and social and economic and cultural meaning,” Peiss says. “I think we should do so with a careful understanding that how we adorn the body and how we fashion our looks and ourselves matters.”

Though the zoot suit is largely gone, it is not forgotten. It reemerged in the late 1960s with the rise of the Chicano Rights Movement, and as a sort of retro fashion in the early 1990s with the revival of swing music and dance. In 2001, the swing band Cherry Poppin’ Daddies released an album called “Zoot Suit Riot.”

“It keeps returning because it is an extreme style of men’s dress, and most men wear relatively conservative styles, which tend to make them inconspicuous,” Peiss says. “It continues to have a hold on the imagination.”