Cities, according to W. Donald McTaggart, are "crucibles" in which art, literature, commerce, and technology are developed and fused. In a two-part online course on the history of the world's cities, Mr. McTaggart, an emeritus professor of geography at Arizona State University, asks students to explore how these crucibles have developed, and how they exert such an influence on those who inhabit them.

The course, "Cities of the World," was traditionally offered in a lecture-hall setting by Arizona State's geography department. But when its instructor retired and the course lapsed, Mr. McTaggart -- who lives in Albuquerque and now teaches some classes at New Mexico State University -- took it on as a distance-learning project.

When he began teaching the course, Mr. McTaggart says, he felt that the future of geographic study was in information
technology -- in CD-ROM atlases and in online databases and maps. Although online geography has been slow to develop, he says, the Web still includes a wealth of useful material. He has made that material one of the centerpieces of his teaching: Students in the class must download free mapping software so that they can view maps and often-complex sets of geographic data.

Each section of the course lasts one semester. In the first semester, Mr. McTaggart covers cities in ancient and medieval Europe and Asia. He also touches on more recent developments, including the explosion of industrial metropolises in England and the effects of cities planted by Europe's imperialist nations in Africa. The second part of the course focuses on urban growth and development in the Americas.

Title: "Cities of the World I"

Institution: Arizona State University

Instructor: W. Donald McTaggart, an emeritus professor of geography

Course content: The course explores "the city as a phenomenon which has supported various forms of development that have contributed to civilization," according to Mr. McTaggart. Its main emphases are geographic and historical, but it also draws on elements of art history and architecture. "The central objective," he says, "is to make people think about the city in a way they haven't before."

How delivered: The semester-long course is divided into weekly lessons, which typically consist of a chapter from a textbook and additional materials on the Web site, which include notes, maps, graphs, and photographs.

Mr. McTaggart and his students regularly open threads on the course's discussion board, where they converse about issues drawn from the texts and from current events. After the September 11 terrorist attacks, students began to talk about the vulnerability of cities and the nature of Afghanistan's cities in relation to the nation's countryside.

Course requirements: Every 10 days, students turn in short assignments in response to the readings and online information. At the end of the semester, they complete term papers based on independent research into topics of their choosing. Some term papers take an in-depth look at the history or arrangement of a particular city. Others are comparative studies: Several students have chosen two cities that have suffered from major natural disasters and analyzed the cities' responses.

When offered: The first section of the course meets in the fall, the second in the spring.

Enrollment: Mr. McTaggart estimates that about 45 students complete the course each year.

Instructor comment: For Mr. McTaggart, online learning's greatest boon is its flexibility. The current educational ethos is one of customization, he says, and distance education offers students the most customizable education. "We don't think of a course as creating an experience that will be identical for all students," he says. "Internet courses allow that flexibility to play out."