Jean Monnet, a pragmatist and visionary who worked for peace by building toward the unity of Europe, died yesterday at his home at Houjarray, France, a village 30 miles southwest of Paris. He was 90.

The cause of his death was not disclosed, but he had suffered in recent years from a bronchial condition.

Although he never held cabinet rank, Monnet was regarded as one of the principal European statesmen of this century. His vision was of a Europe in which traditional prejudices and animosities were submerged in institutions in which the good of all would be represented. His Europe would work in parthership with the United States for the peace of the world.

If the fulfillment of his goal remains to be achieved, his successes were nonetheless formidable and they have had far-reaching effects on the lives of Europeans. They were based on Monnet's belief that practical, selfinterested economic cooperation could serve as the basis for future political forums that would transcend national boundaries.

Monnet was the principal architect of the European Coal and Steel Community, which began to operate in 1952. He was largely responsible for the creation of Euratom, the agency that develops peaceful uses of nuclear energy on the continent. He played a major role in the formation of the European Economic Community, or Common Market, which came into being in 1957.

The Common Market originally was composed of Belgium, France, West Germany, Luxembourg, Italy and the Netherlands -- the same nations that formed the coal and steel community. On Jan. 1, 1973, Britain, Denmark and Ireland were admitted.

This week, eight of the nine Common Market members established a European monetary system, another step toward unity. Britain is not officially a member of the monetary system, although in practice it is a participant.

In June, voters representing 260 million Europeans will hold the first elections for members of a supranatinal European parliament.

All these developments are to an important degree the result of the work of Jean Monnet, whose last position was the presidency of the Action Committee for the United States of Europe, a voluntary organization. He founded the group in 1955 and worked through it until May 9, 1975, when it was disbanded on the 25th anniversary of Monnet's proposal to the late Robert Schumann, a foreign minister and premier of France, for the formation of the coal and steel community.

The action committee was made up of representatives of political parties and trade unions in Western Europe with the exception of the communists. At one time or another its membership included 21 former heads of government.

Monnet played a role in many of the great events of the 20th century. During World War I, he worked on an Anglo-French committee to allocate shipping and other war resources. He worked at the League of Nations at various times between the wars. He helped reorganize the currencies of Poland and Romania.

He also tended to his family's cognac business in France, made a fortune on Wall Street, lost it in the Crash in 1929, and organized finances for railroads in China.

During World War II, he persuaded Winston Churchill to propose a full political union with France in an effort to stave off a French surrender to the Germans in 1940. The effort was unsuccessful. Later, he helped persuade president FranklinD. Roosevelt to undertake the Lend Lease program for supplying the Allies. Roosevelt proclaimed that the United States would be "the arsenal of democracy."

In the immediate postwar period, Monnet reorganized the French economy, and with help from the Marshall Plan, increased production to 50 percent more than prewar levels in five years.

The membership of the action committee is evidence of Monnet's range of contacts in places of influence. Indeed, much of his work was carried on out of public view and a French commentator once said he was "the most celebrated unknown figure of our history."

George Ball, a former U.S. undersecretary of State and a close friend of Monnet, described him as "the supreme practitioner of personal diplomacy. And he practices that art with unfailing perception on the loci of power and with an extraordinary singlemindedness."

In his memoirs publiched last year, Monnet said, "My sole preoccupation was to unite men, to solve the problems that divide the, and to persuade them to see their cemmon interests. I had not set out with this intention, and it was only a long time later that I came to any such conclusion. Only then, urged on by my friends or by newspapermen to explain the point of my work, did I come to realize that I have always been drawn towards union, towards collective action. I cannot say why, except that nature made me that way."

He stated the case for unity and peace in a speech in New York in January 1963.

"The worst enemtes of freedom have been and still are, the spirit of domination and its consequences, the threat of war," he said. "While within our frontiers we have organized liberty and, by mutual consent, maintained the rule of law that largely eliminates the spirit of domination, internationally we are still maintaining peace by force. Now we must go beyond frontiers and create new forms of relationships between countries."

Inevitably, there were occasions when Monnet's arguments fell on deaf ears. In August 1954, the French National Assembly refused to ratify the European Defense Community. Under the EDC, which had strong backing from the United States, a multinational European army would have been raised.

The failure of this plan was a factor in Monnet's decision to retire as president of the coal and steel community in 1955, and continue his work as a private citizen.

In 1958, Gen. Charles de Gaulle emerged as France's leader and savior. De Gaulle set as his mission the reestablishment of a strong and independent France. It was only from a position of pride and strength that France could take its rightful place in Europe and the world, he felt.

This notion ran counter to the ideas of Monnet. He and de Gaulle -- they had been colleagues in World War II -- were in frequent and acrimonious disagreement over the next decade as de Gaulle vetoed Britainhs entry into the Common Market in 1963 and later withdrew from the NATO military alliance. De Gaulle stood for the nationstate in the classic sense. Monnet championed centralized institutions in which nationalism would be reduced.

But on Monnet's 90th birthday last Nov. 8, President Valery Giscard d'Estaing of France said Monnet would leave the world the memory "of a man who has shown by his example that for those who know how to put their analytical incidity, their ardent imagination and their strength of will at the service of a great idea, everything is possible."

Edward Heath, who was prime minister of Britain when that nation joined the Common Market, said of Monnet: "I think there are few men in the world more persistent than he is."

In 1975, former secretary of State Henry A. Kissinger said during the presentation of an award to Monnet, "There is no individual who has made a greater difference and has changed political life more than the man we are honoring today."

On receiving news of Monnet's death, the State Department issued a statement that hailed Monnet as "A great democrat and a visionary builder of Europe. The European institutions which we know today are in large measure the result of his dedication and will stand in history as a shining monument to him. Jean Monnet was a man of integrity, decency and intelligence who concentrated his life on a single ideal: the unity of the West."

A department spokesman said President Carter and Secretary of State Cyrus Vance would send messages of condolence to Mrs. Monnet.

Jean Monnet was born in Cognac, France, where his family was engaged in purveying the famous brandy that bears the district's name. He attended local schools with a view to entering the family business. Although he had the opportunity to go to university, he turned it down. At 16, he joined his father in his work, and at 18 the young Monnet began a series of trips abroad to sell the family product. Among other places, he traveled to the United States and Canada.

But throughout his life he returned to the Cognac region. His sense of place and family remained strong.

Of his father, he wrote in his memoirs: "His view of mankind was optimistic, but I have not inherited it completely. Quite early in life, events taught me that human nature is weak and unpredictable without rules and institutions."

Of his mother he said: "I may have my father's imagination. But my mother taught me that nothing can be achieved unless it is built on reality. She distrusted ideas as such. She wanted to know what was to be done with them."

Perhaps the most difficult time Monnet ever faced -- certainly a time as difficult as any -- was the situation in Europe in 1950.

The Cold War was in full swing. The Marshall Plan had yet to make a major impact on the economic recovery of Europe, and it appeared that a new war could break out on the continent. War had erupted in Asia: the Korean conflict began in June 1950.

The western European states were weak politically and economically. The colonial powers -- Britain and France foremost among them -- still held most of their overseas possessions, and this tended to reinforce nationalist sentiments at the expense of collective European ideas.

Monnet's solution was the pooling of the steel and coal resources of France and Germany. This became the coal and steel community two years later, and its impact was almost immediate. The pool made available to the six member states the basic resources of economic recovery.

"It was the simplest and yet the hardest solution," Monnet said later. "All the vested interests were against it."

Three years later,, Monnet, having served as "the first European civil servant" as head of the steel and coal community, retned to form the Action Committee for the United States of Europe.

He and his wife, Silvia, made their home in a thatched-roof farmhouse at Houjarray near the forest of Montfort L'Amaury.

They had met at a dinner party in Paris in 1929. He was a bachelor in his early 40s. She was 20 years younger, and the wife of an Italian businessman.

"We forgot the other guests," Monnet wrote in his memoirs. "We soon decided that we must be together for life. Many obstacles stood in the way. Silvia was married under Italian law, which forbade divorce.

"I looked into a number of solutions: I found that divorce and remarriage were possible under Soviet law. We decided on that solution. We met in Moscow on Nov. 13, 1934, and everything went as simply as could be. Many years later, Monseigneur Henri Donze, bishop of Tarbes and Lourdes and a great friend of the family, married us in Lourdes itse.f."

It was to Houjarray that Monnet used to repair to think out his decisions while walking in the forest of Montfort L'Amaury. It was there he lived his last years, walking in his garden, watching his wife at her painting, receiving visits from his two daughters, anne and Marianne, and his grandchildren and his friends.

"The seasons go by," he wrote. "I had never noticed their passing before -- I was too much distracted by activities in town. Spring comes round once more. Someone says to me: "There will be no spring for Europe in this year of grace 1976.' Perhaps; but we should keep on course, and not worry am certain that the passing seasons will lead us inevitably towards greater unity."

To the end of his life, Jean Monnet retained faith in his vision and its viability.