World-renowned anthropologist Paul Farmer stressed the role of government in securing the right to health care, in a speech to a packed Sanders Theatre Friday night.

In an evening that combined weighty issues and humor, Farmer, the Presley professor of social medicine at Harvard Medical School, answered questions on issues from Haiti to Rwanda, and from the importance of civil activism in the U.S. to the process of building a public health system in Malawi.

Farmer, the founder of Partners in Health, a Boston-based nonprofit organization with projects in the U.S., Latin America, and Russia, said that although the success of projects like those he runs are dependent on the commitment of governments to providing basic health rights, Partners in Health would not necessarily avoid getting involved in countries where the regime is unwelcoming.

“We need to be humble about what we’re doing,” Farmer said in a phone interview after the event.

Farmer said he was skeptical about Massachusetts’ recent legislation requiring all state residents to have health insurance.

“Passing a law requiring people to purchase insurance is not the same as a law insuring health care,” he said to enthusiastic applause.

Farmer’s appearance was part of the Cambridge Reads program, a citywide book club led by the Cambridge Public Library, which discusses one book each year and holds a meeting with the author. This year’s choice was “Mountains Beyond Mountains,” written by Pulitzer-prize winner J. Tracy Kidder ’67 about Farmer’s work.

Kidder also spoke briefly on Friday night, introducing Farmer.

Amanda Darling, marketing manager for the Harvard Book Store, which is one of the program’s sponsors, said that this year’s turnout was by far the largest in the program’s history. It was the first time that Sanders Theatre hosted Cambridge Reads, she added.

Farmer said that public health awareness and activity at Harvard has “skyrocketed” in recent years. He estimated that when he had been a medical student at Harvard in the 1980s, five to 10 percent of the student body was aware of public health concerns, as opposed to as much as half today.

Farmer, who currently teaches at the Harvard Medical School and who co-taught an undergraduate freshman seminar on AIDS in the Caribbean in the spring of 2005, said the change at Harvard is due mainly to the varied projects students are involved in.

When in need of knowledge or expertise, he said, he “would be as likely to turn to one of them as anybody at Harvard.”