Derek Humphry, a British-born journalist whose experience helping his terminally-ill wife end her life led him to become a crusading pioneer in the right-to-die movement and publish “Final Exit,” a best-selling guide to suicide, died on Jan. 2 in Eugene, Ore. He was 94.

His death, at a hospice facility, was announced by his family.

With a populist flair and a knack for speaking matter-of-factly about death, Mr. Humphry almost single-handedly galvanized a national conversation about physician-assisted suicide in the early 1980s, a period when the idea had been little more than an esoteric theory batted around by medical ethicists.

“He was the one who really put this cause on the map in America,” said Ian Dowbiggin, a professor at the University of Prince Edward Island and the author of “A Concise History of Euthanasia: Life, Death, God, and Medicine” (2005). “The people who support the notion of physician assisted suicide absolutely owe him a big thanks.”

In 1975, Mr. Humphry was working as a reporter for The Sunday Times of London when Jean Humphry, his wife of 22 years, was in the final stages of terminal bone cancer. Hoping to avoid prolonged suffering, she asked him to help her die.

Mr. Humphry procured a lethal dose of painkillers from a sympathetic doctor and mixed them with coffee in her favorite mug.

“I took her the mug and told her if she drank it she’d die immediately,” Mr. Humphry told The Daily Record in Scotland. “Then I gave her a hug, kissed her and we said our goodbyes.”