Agassiz Professor of Geology Steven J. Gould appeared on the cover of News-week in 1982, but only one Harvard fan came up to him on the street to congratulate him. Indications to the contrary aside, however, Gould is easily one of the most popular teachers at Harvard.

Every fall for the past two years, students have engaged in the ritual of entering the lottery for his course, Science B-16, "The History of the Earth and of Life." This fall was no exception, with more than 500 students vying for 250 slots.

Much of the course's popularity stems from Gould's reputation and personal appeal. Lectures are filled with the professor's taut energy and obvious excitement for his subject and students. The historical and literary allusions and illustrations he uses make the class more than a lesson in plate tectonics or evolution. Rather, the course seems, surprisingly, to live up to its rather ambitious title.

Gould's enthusiasm is infectious. He leaves the indelible impression that he is interested in almost anything--from Mickey Mouse in one lecture, to medieval cathedrals, batting averages or the panda's thumb in another.

"He has become a propagandist," says Professor of Anthropology David R. Pilbeam, because "he's such an effective proselytizer and explainer of what's going on."

But that is not to say he hasn't made his mark in the scientific field. Gould's extensive writing has made him "the bulldog of evolutionary biology," Pilbeam says, adding that he is in "qualified agreement" with Gould's theory of evolution.

Unlike traditional Darwinians, Gould believes that evolution occurs in fits and starts--long periods of stability in the nature of each species followed by brief periods of change.

"[Gould] has been a well known scientist for over 10 years," says Assistant Professor of Biology Pere I. Alberch, adding that the media have been slow to catch on.

One species does not give way immediately to another, Gould argues, but it coexists with a cousin-species until one eventually prevails for a variety of reasons. The diagram of evolution he flashes on a screen in Science B-16 resembles a bush whose branches represent different experiments in the way an animal type finds to survive.

The branches either grow upward, splitting into two or three branches because different species types can survive, or they stop short, indicating that a particular experiment failed and the species has grown to extinction.

"Usually the articles in magazines oversimplify my theories," Gould says. "Often they write about punctuated equilibrium or adaptation as if there were only two sides, as if I'm on one, unorthodox side and everybody else is on the other."

Gould shares the credit for punctuated equilibrium with Niles Eldredge, a paleontologist at New York's Museum of Natural History.

His abilities as both a scientist and a propagandist were called on during his testimony defending evolution at the landmark 1981 trial of Arkansas' law requiring that creationism be taught in schools.

"It was the most fun aspect of my public life," Gould says. As a result of Gould's and other scientists' testimony, the law was thrown out.

Now Gould is attempting a retreat from publicity. "The most important thing in life is my research and my students, and I have to keep my time for that," he says. But recently Gould was again in the news with the CBS show "60 Minutes" doing an episode on him.

Little seems to slow Gould down, but the discovery of cancer in July 1982 forced him to curtail his hectic pace. Nevertheless, throughout his year-and-a-half bout with cancer, he has continued to teach courses and work on his pet project, studying and cataloguing the characteristics of the Cerion, a Bahamas land snail.

Since Gould discovered the cancer--mesothelioma, an asbestos-related tumor--he has fought it with surgery, radiation and chemotherapy. He has lost 50 pounds since then, but the treatment has apparently been successful.

"It's a part of my life that can't be denied," Gould says.