During his third and finally successful campaign for the French presidency in 16 years, Francois Mitterrand was fond of recalling that he tried to escape from a German prisoner of war camp three times, twice falling just short of an arduous journey to freedom. "The third time was the good one," he said.

"Obstinate" and "hard-headed" are the most common words members of his family have used to describe the young Mitterrand as a child, growing up in Jarnac and Angouleme the fifth of eight children in a bookish provincial family steeped in Roman Catholicism of the liberal Christian Democratic variety that was relatively uncommon in the France of the time.

His father was a railwayman who became a stationmaster, inherited a vinegar distilling business and gave his family a comfortable middle-class life. But hard work and duty were watchwords. All four brothers made it into the French Who's Who: one as a literature professor who has written studies of muckraking novelist Emile Zola, another as an Air Force general who runs one of France's leading nationalized aeronautics companies, a third as a leading industrial manager -- and Francois.

Mitterrand makes people want to label him, to define him, but every attempt seems to founder on his elusive ambiguity that makes a contradictory description seem just as true.

Often dismissed as nothing but a political hack who was so available for deals that he served 11 times as a cabinet minister in the revolving-door governments of the Fourth Republic, Mitterrand is also the only leading French politician who manifestly exists for other things besides politics: reading, writing, strolling in his beloved central French countryside or along the quays of Paris, contemplating pretty women. Mitterrand watchers often remark that no matter what he is doing, part of him always seems to be "elsewhere."

He is a man who seeks solitude but is fiercely loyal in his sparingly granted friendships. His key campaign poster when he first ran against Valery Giscard d'Estaing in 1974 showed him walking alone in the country with the inscription "Socialism, an idea that is making its way." This time, the theme poster showed him with a village church in the background and the slogan "The Trnaquil Power."

His reaction to news of his election yesterday seemed to be the measure of the personality he has created in successive overlays. He was standing in the dining room of the small Hotel du Morvan, where he always stays when he visits his National Assembly constituency in Chateau Chinon, talking to a knot of journalists. He was discussing the weather patterns in the Morvan region. Someone brought him news that computer projections that could not be made public for another 90 minutes showed that he had won. Without changing his expression, he said, "That's better than otherwise."

Then, he finished what he had been saying about the local climate and refused to be drawn into political discussion.

His first gesture today as president-elect was to pay a visit to the Paris tomb of a lifelong friend, Georges Dayan, a Socialist organization man who died two years ago. His intimates describe him as generous, but the surest way not to get something they want from him is to make the mistake of asking for it, they say.

Nobel Prize novelist Francois Mauriac, the leading Catholic writer of his generation and an old family friend, pinned on Mitterrand the label that probably did him the most harm -- "the Florentine" -- with all the connotations of Machiavelli, the arts of political intrigue conducted with a fine Italian hand.

Mitterrand has pushed his taste for paradox by making it known that he has been working off and on for the last 20 years on a novel about Lorenzo the Magnificent, the best-known of the Medicis.

The parallels between Mitterrand and the man he has most ardently combatted in French political life, Charles de Gaulle, are haunting. They both in their times have been the most private men in public life. Both are high literary stylists without being great writers. Both have been steeped in Catholic culture without being believers. They shared a mystical attachment to France, a personal authoritarianism, a taste for clothing themselves in mystery.

Yet, Mitterrand describes each of their personal encounters as something of a disaster. Mitterrand was long criticized by the Communists for his statement while he was interior minister at the start of the Algerian rebellion: "Algeria is France; the sole negotiation possible is war." When de Gaulle returned to power in 1958, supposedly to keep Algeria French, Mitterrand was one of his first and loudest opponents, writing a book denouncing the general's new Fifth Republic entitled "The Permanent Coup d'Etat."

Mitterrand, who is now to become the fourth president of that Fifth Republic, was in the view of a man who has often observed him in relaxed moments "just too much like the general [de Gaulle] ever to be able to get along with him."

Now that de Gaulle is gone, however, Mitterrand has not hesitated to wrap himself in his mantle. "Like de Gaulle," said Mitterrand in a favorite election campaign theme, "I will have need of all the French people" -- a statement meant to convey the idea that he can use the Communists just as the general did.

Mitterrand never let himself be impressed by anyone, least of all de Gaulle. As Mitterrand once wrote, "There is no force in the world, no philosophical, religious, state, or money force from which I am not totally free. And if there were a source of pride in my life, that would be it."

The force from which he has most deliberately tried to keep himself free is the French Communist Party. He is the first French Socialist leader who has approached the Communists without any political inferiority complexes. He has obviously decided that anything the Communists can do to his Socialist Party, he can do back to them. If the Communists think they can "pluck the Socialist bird," then there is no reason that Mitterrand cannot try to "pluck the Communist bird," seems to be his reasoning.

But, Mitterrand once said, "I was not born a Socialist. . . . To make things worse, I never displayed any precociousness about it."

He spent 25 years of his political career, starting at 30 as France's youngest postwar minister, as a liberal moderate in a tiny hinge party positioned at the center of the political spectrum so that it was bound to be in any combination from center-right to center-left.

It was only in 1971 that he joined the then-moribund Socialist Party, breathing new life into it in a series of maneuvers that left even admirers of his tactical skills full of new wonder. But the basic decision that permitted him to revive the party was to remove its image as a handmaiden of conservative governments and policies by insisting that it would only make alliances on the left, meaning with the Communists. It was a decision that erased the party's opportunistic image.

That route to power was blocked, however, because the Communists showed that they were unwilling to take the risk of coming to power with a powerful Socialist Party that could treat them on an equal footing. As in so many instances in his life, Mitterrand turned that failure into an asset. A Socialist leader who had made a genuine try to govern with the Communists was the only one in a position to steal large numbers of votes from them.

It was the ultimate paradox in Mitterrand's life. He succeeded in becoming president only because he had conducted a visibly unsuccessful policy. b