The diplomat-politician, scholar and writer, succumbed to a spreading cancer that had caused the loss of his right eye two years ago.

The easy-mannered leader known to friends as Mike since his athletic and studious boyhood, had lapsed into a coma yesterday and died at 11.40 p.m.

His career was highlighted by the award of the Nobel Peace Prize for his work in helping to organize a United Nations peacekeeping force in the Middle East in 1956. That brittle peace lasted for about a decade, collapsing with renewed Arab-Israeli war in 1967 on the eve of Mr. Pearson's retirement from active politics.

His years as Prime Minister, despite a lack of majority in the Commons, were marked by a succession of welfare measures such as national medical care insurance: recognition of Quebec's special place in Confederation; trial abolition of capital punishment, and - amid controversy- adoption of the Canadian flag instead of the old Red Ensign bearing the union Jack.

Unfinished at his death were the Pearson memoirs. The first volume, titled Mike and covering the years until he entered partisan politics, was published earlier this year. A second column is complete and a third was partly written.

Present at the Pearson home in the rich Rockliffe Village district of Ottawa were his wife Maryon, son Geoffrey, an External Affairs officer teaching at University of British Columbia, and daughter Patricia, wife of Dr. Walter Hannah, chief of obstetrics and gynecology at Women's College Hospital in Toronto. The Pearson children had come to Ottawa soon after their father had been flown home Christmas Eve by Government plane from an abbreviated Florida holiday.

Although the final illness had been diagnosed late in the fall, Mr. and Mrs. Pearson had flown south to Florida Dec. 17 for a scheduled three-week rest. The disease advanced more quickly than expected and the holiday was cut short.

Funeral plans were understood to include a service at Christ Church Anglican cathedral in Ottawa, scene of previous state funerals, and burial across the Ottawa River in Wakefield, Que., and area of natural beauty Mr. Pearson grew to love during spells at a summer home on nearby Barrington Lake. Announcement of the death came through the office of Prime Minister Pierre Trudeau, Mr. Pearson's successor. It said Mrs. Pearson had requested that any individual tributes be in the form of contributions to the Canadian Cancer Society.

"Arrangements are now being made to accord to Mr. Pearson a state funeral. Details will be announced shortly by the Secretary of State."

There are two former living Prime Ministers: Louis St. Laurent, 90, who served from 1948 to 1957, and John Diefenbaker, 77, Prime Minister from 1957 to 1963 and still MP for Prince Albert, Sask. Before the death was announced, Mr. Diefenbaker urged Canadians to pray for Mr. Pearson.