Marshall McLuhan, the Canadian-born writer and lecturer who coined the phrase "the medium is the message," died in his sleep at his Toronto home yesterday at the age of 69. According to his daughter, Stephanie, he apparently died of a stroke.

Mr. McLuhan became the standard-bearer of the "media age" he helped to christen and characterize after the publication of his most celebrated book, "Understanding Media" in 1964.

Until his retirement last year after a stroke and an operation, he had been director for 14 years of the University of Toronto's Marshall McLuhan Center for Culture and Technology. In 1967, he underwent over 22 hours of surgery for a brain tumor.

At the height of his fame in the late 1960s, Mr. McLuhan was dubbed "the oracle of the electric age" by Life magazine. One commentator noted that he had "become that phenomenon of our times, the In intellectual celebrity." Mr. McLuhan disarmed critics who called him fuzzy or obscure by admitting that his own theories caused him bewilderment. "I don't pretend to understand it," he was once reported to have said. "After all, my stuff is very difficult."

His "stuff" included more than 15 books on communications, literature, the arts, sociology, education and other subjects. Besides "Understanding Media," which explored the new electronic media as factors that transformed modern civilization, his best known works included the earlier "The Gutenberg Galaxy" (1963), in which he introduced the phrase "global village" as a metaphor for contemporary society. "The Mechanical Bride" (1951), and "The Medium is the Message," the title of which is a typical McLuhan pun, in this case on his own popular catchphrase.

Mr. McLuhan's flavor is captured in his own introduction to a second edition of "Understanding Media" in which he attempts to clarify the statement, "the media is the message." "Any technology," he writes, "gradually creates a totally new human environment. Environments are not passive wrappings but active processes. . . . The young student today grows up in an electrically configured world. It is a world not of wheels but of circuits, not of fragments but of integral patterns. The student today lives mythically and in depth."

Mr. McLuhan taught at a number of colleges and universities in the United States and Canada, and was in lively demand as a public speaker. At the request of director Woody Allen, he made a cameo appearance in the movie "Annie Hall," expounding and defending his ideas.

Mr. McLuhan's concepts and pronouncements have stirred large amounts of controversy. Estimates of his intellectual merits have ranged from a New York Herald Tribune reviewer who declared him "the most important thinker since Newton, Darwin, Freud, Einstein and Pavlov" to such detractors as Dwight MacDonald, who summarized "Understanding Media" as "impure nonsense, nonsense adulterated by sense."

Herbert Marshall McLuhan was born July 21, 1911, in Edmonton, Alberta, to a Protestant family (Mr. McLuhan later converted to Roman Catholicism) of Scotch-Irish descent. His father was a real-estate and insurance salesman; his mother an actress and monologist.

He entered the University of Manitoba intending to study engineering but after a summer with books he declared, "I read my way out of engineering and into English literature." After earning bachelor's and master's degrees at Manitoba, he attended Cambridge University for graduate studies and was awarded a PhD in English literature in 1942.

His teaching career started at the University of Wisconsin in 1936, and took him, after several intermediary posts, to the University of Toronto a decade later. In the early 1950s he directed a Ford Foundation seminar on culture and communication, and in 1659-60, a joint media project of the U. S. Office of Education and the National Association of Educational Broadcasters.

In his first published book, "The Mechanical Bride," he inveighed against "the pressures set up around us today by the mechanical agencies of the press, radio, movies and advertising," but the work didn't attract much attention at the time. Far more impact came with "The Gutenberg Galaxy," in which Mr. McLuhan seemingly became an advocate of the technologies he had previously criticized, arguing that by turning the world into a "global village" and restoring "tribal" patterns, the electronic media were reducing the fragmentation of society that the advent of printing had brought about.

Then, in 1964, the landmark "Understanding Media: The Extensions of Man" elaborated on the theme of the "cool," "non-linear" media of television, in particular, as effecting a wholesale restructuring of mass consciousness. His distinction between what he called the "hot" media (such as print) and the "cool" was the subject of endless dispute, but so great was the focus on his ideas that the term "McLuhanism" was accepted as an entry for the Oxford English Dictionary.

Mr. McLuhan had a gift for aphorism and an enormously wide field of reference; he was apt to make provocative, quotable statements on almost any subject. A typical example: "The coffee break was one of the major social revolutions in history. It went directly against the Protestant work ethic. You're actually expected to socialize with the people you work with for 15 minutes twice a day."

In a interview for The Washington Post in 1977, Mr. McLuhan voiced characteristically salty and intricate opinions on everything from the "Roots" series on television to instant replay, the generation gap, the death of the novel, and the hemispheres of the brain. Among his remarks:

"Gutenberg made everybody a reader. Xerox makes everybody a publisher. Now when everybody becomes a publisher, strange things begin to happen."

"The violence of the media is enormously bigger than anything on the programs. And let me say, violence means literally to cross boundaries, violate people's privacy, to violate people's rights. Pornography, for example, is a huge violence crossing people's right to privacy."

Another example, which appears to contradict itself in a quintessentially droll, McLuhanesque way: "By the way, I do not make value judgments. I simply try to discover what's going on. And most of what's going on I find very painful and very tiresome."

Mr. McLuhan was the recipient of numerous awards, honors and medals, including citations from the governments of Italy and Great Britain.

He is survived by his wife, Corinne, and six children.