Robert C. W. Ettinger, a physics teacher and science fiction writer who believed death is only for the unprepared and unimaginative, died July 23 at his home in Clinton Township, Mich.

He was 92 and had suffered declining health in recent weeks, said his son David, who could not specify a cause. “We’re obviously sad,” said the younger Ettinger. But “we were able to freeze him under optimum conditions, so he’s got another chance.”

Mr. Ettinger is widely considered the father of the cryonics movement, whose adherents believe they can achieve immortality through quick-freezing their bodies at death in anticipation of future resurrection.

Mr. Ettinger’s frozen body is being stored in a vat of liquid nitrogen at a nondescript building outside Detroit, home to more than 100 fellow immortalists — including his mother and two wives — who are awaiting revival.

If all goes as Mr. Ettinger envisioned, he will remain in a period of icy stasis for decades — or perhaps centuries — however long it takes for doctors, armed with technology of the future, to defrost him and restore him to good health.

“Our patients are not truly dead in any fundamental sense,” he told a New Yorker reporter in 2010.

Mr. Ettinger was a little-known community college professor in the mid-1960s when he wrote the founding document of cryonics, “The Prospect of Immortality,” a manifesto that described the practical and moral aspects of deep-freezing the dead.

Introducing what he called the Freezer Era, Mr. Ettinger described a world in which people would become nobler and more responsible as they were confronted with the reality of living forever.

And if Earth became too crowded with long-lived humans? “The people could simply agree to share the available space in shifts,” he wrote, “going into suspended animation from time to time to make room for others.”

Originally self-published in 1962, the book was put out by Doubleday in 1964. It struck an “instantaneous public nerve,” according to Life magazine, and launched Mr. Ettinger to celebrity.

Mr. Ettinger’s deep-freeze dogma was covered in the New York Times and Newsweek, and he was invited to appear on talk shows hosted by Johnny Carson and David Frost. Once, Mr. Ettinger told the New Yorker, he shared a stage with conservative commentator William F. Buckley.

“He was aghast at everything I said. He thought it was immoral, unethical, unsanitary, against the will of God!” he recalled, laughing. “Buckley understood nothing.”

Most scientists also scoffed at Mr. Ettinger’s vision, but his manifesto came as the world was adjusting to the atomic bomb, Sputnik’s robotic spacecraft and a host of other sci-fi-seeming technologies. To many at the time, Mr. Ettinger’s optimism seemed appropriate.

His book helped spur the development of a number of organizations devoted to deep-freezing the dead, one of which — the now-defunct Cryonics Society of California — successfully froze a person for the first time in 1967.

The next decade, Mr. Ettinger founded his nonprofit Cryonics Institute. He served as president until 2003, attempting to democratize immortality through discount rates. Total fees for guaranteed icy perpetuity start at about $28,000, whereas a main competitor, California-based Alcor Life Extension Foundation, charges almost five times as much.

Mr. Ettinger saw a period of growth in the industry despite the fact that science has yet to pull a corpse out of cryo-preservation. Today, his institute houses 106 human patients and dozens of pets, including dogs, cats and at least one parrot.

About 900 dues-paying members around the world plan to be frozen when their time comes. “We are making steady progress against entrenched tradition,” Mr. Ettinger wrote last year in response to the Times magazine article about cryonics. “The tide of history is with us.”

Robert Chester Wilson Ettinger was born Dec. 4, 1918, in Atlantic City. He was a boy when he moved to Detroit and read a short story that sparked his interest in immortality.

“The Jameson Satellite,” by Neil Jones, told of a dying professor who launched himself into space — where he was found millions of years later by aliens who brought him back to life by transplanting his brain into a mechanical body.

“Why wait for aliens?” Mr. Ettinger later told a reporter. “Why not do it ourselves?”

He became further interested in the possibilities of medical technology during World War II, when he was badly injured by German mortar while fighting in Europe in the days before the Battle of the Bulge.

He attended Wayne State University under the G.I. bill and graduated with a bachelor’s degree and two master’s degrees, in math and physics. He penned his cryonics manifesto after being inspired by a French scientist who found that frog sperm was viable even after being frozen.

His other books included “Man Into Superman: The Startling Potential of Human Evolution — and How to Be Part of It.” Published in 1972, it has been described as an important book among transhumanists, who believe new technologies will allow humans to radically overhaul their bodies and extend their lives.

Mr. Ettinger remained most closely identified with cryonics, however. His first patient was his mother Rhea, who died in 1977. “I don’t know if she was very enthusiastic about it,” he said of his mother’s freezing, “but she was willing.”

A decade later, he froze his second patient — his wife Elaine, who died in 1987 and with whom he had two surviving children, David and Shelley.

The next year he married his second wife, Mae. When she died in 2000, she was the institute’s 34th patient.

“If both of my wives are revived,” Mr. Ettinger told the Detroit News last year, “that will be a high class problem.”