Dr. Eric Cassell, a distinguished medical ethicist who urged fellow doctors to shift priorities beyond curing their patients’ diseases to caring for their overall well-being, died on Sept. 24 at his home in East Stroudsburg, Pa. He was 93.

His death was confirmed by his son Stephen.

The author of hundreds of articles and multiple books, Dr. Cassell devoted his career to helping physicians understand how people experience illness and pain and to guiding them in providing compassionate care to patients who are dying.

“Eric was, in my mind, the intellectual father of palliative care,” said Dr. Susan Block, a professor of psychiatry and medicine at Harvard Medical School.

Dr. Cassell, who lectured widely, was a founding fellow of the Hastings Center on bioethics in Garrison, N.Y., where he and colleagues concluded in the early 1970s that most people do not dread death as much as they do suffering.

Mildred Z. Solomon, president of the Hastings Center, said of Dr. Cassell in an email that “his insights have been foundational for many developments in medicine, including the origins of the palliative care movement, patient-centered care, and even disability rights.”

As a professor of public health at the Weill Cornell Medical College in New York and a private practitioner, “he gave voice to the patient experience of illness and changed the paradigm from disease care to person-focused care,” said Betty Ferrel, director of nursing research at City of Hope Medical Center in Duarte, Calif., in a tribute to him.

In “The Nature of Healing: The Modern Practice of Medicine” (2013), Dr. Cassell defined a sick person as one “who cannot achieve his or her purposes and goals because of impairments of functions that are believed to be in the domain of medicine.” Such a person, he maintained, must be clearly distinguished from those who are well.

“We think a sick person is just a well person with a sickness — the same person you’ve always been, except you just happen to have a sickness,” he said in an interview with The New York Times Magazine in 1988. “That isn’t true.”

Rather, he said: “Sickness changes people’s ability to make decisions. They become dependent on the doctor and others to take care of them, and focus on themselves rather than the outside world. So, in many ways they become childlike. They may seem intact in all intellectual respects, but, in fact, they no longer reason like well people.”

Dr. J. Donald Boudreau, interim director of the Institute of Health Sciences Education at McGill University in Montreal, said, also in a tribute, that the concept of “physicianship” that Dr. Cassell had helped develop “argued that a key role of medicine should be to return patients to a sense of well-being, where well-being is based on achieving goals and purposes in life.”

Dr. Cassell was born Eric Jonathan Goldstein on Aug. 29, 1928, in New York to Hyman and Anne (Lake) Goldstein and raised in Queens. His father was a civil engineer for the post office. Dr. Cassell said that he and his brother had changed their surname to approximate the original pronunciation of that of their immigrant grandfather, before it was changed at Ellis Island when he arrived from Russia.

Dr. Cassell earned a bachelor’s degree from Queens College in 1950, a master’s from Columbia University and a medical degree from the New York University School of Medicine. He was a captain in the Army Medical Corps from 1956 to 1958 in France and served his internship and residency at Bellevue Hospital in Manhattan.

In 1971, as a result of an article he had written, he was recruited to the Task Force on Dying at the Hastings Center.

“That literally changed my life, broadened my horizons, pushed me to become literate, and gave substance to a genetic predisposition to philosophy,” Dr. Cassell wrote on his website. “I began to wonder whether a doctor could actually treat patients in a successfully useful and special way because they were dying.”

“Now we know that you not only can,” he added, “but you should.”

He directed the Program for the Study of Ethics and Values in Medicine at the medical college of Cornell University from 1981 to 1986. He retired from his internal medicine practice in 1998.

In addition to his son Stephen, from his first marriage, with Joan Cassell, which ended in divorce, he is survived by a daughter, Justine, from that marriage; his wife, Patricia Owens; his stepchildren, Margaret, Theresa, Shirley, James and Rebecca Owens; a granddaughter; two step-grandchildren; and a step-great-grandchild.

Among his 11 books were “The Healer’s Art: A New Perspective on the Doctor-Patient Relationship” (1976; revised in 1985) and “The Nature of Suffering” (1991).

Dr. Cassell said his conversion to “the new religion of truth” in doctor-patient relationships did not come easily.

“It took me time to get the bloody words out of my mouth, ‘You are dying,’ or ‘Yes, you have cancer,’” he said. “When doctors use euphemisms, they tell the patient and themselves that they’re powerless.”

In cases where a terminally ill patient may prefer death to continued treatment, Dr. Cassell said, “an unspoken agreement” may exist between the patient and a hospital staff that sees its medical mission as something more than just keeping the body alive. Then, he said, the staff’s duty would be to help the patient die in as “pleasant” and “congenial” a way as possible. (Dr. Cassell received hospice care near the end of his life.)

That is why listening to patients and determining how they define their own well-being is so vital, he said, and why “the spoken language is the most important tool in medicine.”