By Brad Wolverton

Glen S. Elder, an associate professor of geography at the University of Vermont who did pioneering research in the field of queer sexuality studies, died on May 21, in Burlington, Vt., of an apparent heart attack. He was 42.

Mr. Elder was a beloved teacher and rigorous scholar who helped write a book exploring sexuality and geography and recently completed a documentary film about the behavior of people crossing the U.S.-Canada border after September 11, 2001.

A native of South Africa, he performed extensive field work there during the end of apartheid and once arranged for a group of Vermont study-abroad students to meet Nelson Mandela.

Despite a relatively privileged upbringing —his family had a maid and a live-in gardener —Mr. Elder was drawn to the lives of the less fortunate. His doctoral research, at Clark University, in Massachusetts, focused on black South Africans who lived in labor hostels and the constraints on their family life. His survey data were later used by the South African government to help track the spread of AIDS.

"He took many risks working in the hostels and in asking the kinds of questions that he did," says Heidi J. Nast, a professor in the international-studies program at DePaul University, who collaborated with Mr. Elder on another project.

After completing undergraduate degrees in geography and English at the University of the Witwatersrand, in Johannesburg, in the late 1980s, Mr. Elder moved to the United States. He received his doctorate from Clark in 1995, the same year he was appointed a visiting assistant professor at Vermont. He was tenured in 2002 and chaired the university's department of geography from 2005 to 2008. Since then he had served as interim associate dean of the College of Arts and Sciences, an appointment that was to be made permanent on July 1. His appointment to a full professorship was to be considered this fall.

At Vermont, he was known for his elegant dress and generous spirit. He wore a tie to work and shined his shoes every morning. Whenever new faculty members arrived on campus, he brought them a bag of food or invited them to lunch.

Mr. Elder was one of the university's most popular professors, winning multiple teaching awards. Even years after taking his courses on Africa or political geography, students would list them as the best and most influential they had taken, said Meghan Cope, incoming chair of the university's geography department, in an e-mail message.

In his research, Mr. Elder also explored the demographic similarities between same-sex and heterosexual couples who seek to marry, finding that gays and lesbians are no different from straight couples in their desire for domestic stability and material comfort. And he helped create the "sexuality and space" specialty group within the Association of American Geographers.

"He was very much on the cutting edge of all sorts of geographical research," says Beverley C. Wemple, an associate professor of geography at Vermont.

And yet it was in an introductory world-geography class where Mr. Elder may have made his biggest mark, say former students and colleagues. A natural lecturer, he enjoyed the "drama and performative aspects" of large classes, he once said.

To demonstrate the globalization of the textile industry, he asked students in that class to look at their clothing labels and shout out where they came from. They named countries from around the world: China, the Philippines, Thailand —and one year, Milan.

"Milan?" Mr. Elder said, snapping to attention. "Who's wearing something from Milan?"

A woman's hand went up.

"On the catwalk, sister!" said Mr. Elder, and he paraded her down the aisle in front of the class.

Students appreciated his sense of humor but also respected his command of the field. "He knew what he was doing, and he was charismatic about it," says Reese Hersey, a former teaching assistant of Mr. Elder's. "He was one of the more inspiring people I've ever seen teach."

For others, Mr. Elder's lessons inspired more than scholarship. Bradley Rink first met Mr. Elder in 1996, when he was applying to Vermont's graduate program in geography. He would become one of Mr. Elder's graduate teaching fellows, help him lead two study-abroad trips to South Africa, and focus his doctoral research in the same areas Mr. Elder studied. Today he is resident director of a study-abroad program at Stellenbosch University, near Cape Town.

Mr. Elder recently served as an external examiner for his former student's dissertation. The two men discussed Mr. Elder's new role as an associate dean. He loved the challenge of it, Mr. Rink says, but missed doing geographic research.

"The wonderful thing is," Mr. Elder told him, "we're minus one queer geographer, but now we're plus one."