President Tito of Yugoslavia, one of the 20th century's boldest revolutionaries and one of its most enduring leaders, died yesterday in the Yugoslav city of Ljubljana three days before his 88th birthday.

An official bulletin said he died at 3:05 p.m. (10:05 EDT) from heart failure. He had undergone two operations in January, including amputation of his left leg to arrest a circulatory ailment, and his doctor's daily bulletins since had listed him in "grave condition," suffering from heart and kidney malfunctions.

A Communist since 1917, Tito became Yugoslavia's unchallenged leader in the fashion traditional to that country's monarch -- as chief of a guerrilla uprising.

Although he had only five years of primary schooling, his lifelong curiosity and passion for travel endowed him over the years with an immense variety of skills. He not only organized an effective guerrila army, but also awarded himself the title of marshal and created the republic of which he was president.

He was a natural diplomat who made himself a world figure for more than three decades and who knew Churchill, Stalin, Nehru, Nasser, Kennedy, and Khrushchev.

In 1948 he refused to take orders from Moscow and took his country out of the Soviet bloc, successfully defying Stalin's determination to destory him and exposing the myth of unchallengeable Russian strength. Ever since then, he steered himself, his party and his country past innumerable political reefs and shoals.

In conducting a highly visible balancing act, Tito became Europe's "Fiddler on the Roof." On one side was a slide toward Stalinism, on the other toward pluralism. He wouldn't go either way, charting a unique course for Yugoslavia. His became an independent Communist country within Moscow's sphere but beyond its grasp, strongly allied with the Third World movement (which he helped create) yet on good terms with most Western nations. m

In the years after his break with Stalin, the United States extended more than $4 billion inaid an credits to his country in an effort to make this rift irreversible and deny the Russians access to the strategically located country.

At home, Tito's regime changed in style if not in substance. Switching from a Soviet-style command economy to workers' self-management and a free market, he introduced a degree of freedm greater than in any Communist country.

After the initial years, when he ruled through fear backed by force, Tito's system changed into one based on hope backed by force.

Tito also was a contrast to his contemporaries -- the bloodthirsty Stalin, the maniacal Hitler, the fatuous Mussolni, the erratic Khrushchev, the stolid Franco. He was more humane, less murderous, more willing to experiment. He enjoyed the pleasures of power, openly and unabashedly living in the style of his royal predecessors. And although he considered himself a Marxist, he was bored by abstractions and never took ideology very seriously, at least not as a way to interpret the actions of others.

Tito was born on May 7, 1892, in the Croatian village of Kumrovec. His name was Josip Broz, but later as a Communist operative he gave himself the name of Tito. His father was a Croatian peasant, his mother a Slovenian landowner's daughter. He was the seventh of 15 children, eight of whom died in infancy, and he was reared as a Roman Catholic.

He left home in 1907 to work as a waiter in a cafe in the nearby town of Sisak, then became a locksmith's apprentice. In Zagreb in 1910, he joined the metal workers' union and the Social Democratic Party. He traveled to Ljubljana, Trieste, Mannheim, Pilsen and Munich before settling as a skilled mechanic and test-driver at the Daimler Benz auto works outside Vienna.

In 1913, he was drafted into the Austro-Hungarian Imperial Army, where he became a sergeant-major and commander of a scouting platoon on the Carpathian Front in World War 1. On Easter morning, 1915, he was wounded and captured by Circassian troops of the Imperial Russian "Savage Division," and was taken -- first to recover, then to work -- to the Volga region, the Urals and Siberia.

When the Russian Revolution broke out, he hopped a train to Petrograd (now Leningrad) and took part in the July 1917 Communist demonstrations during which Lenin's Bolsheviks made their first unsuccesful attempt to overthrow the democratic Provisonal Government.

He was arrested, briefly imprisoned and then sent back to Siberia, but released when the Communists took power. During the Russian Civil War, he served in the Red Guard at Omsk and also wandered for months with Kirghiz tribesmen in Central Asia. At Omsk, he married in the first of his three wives, Pelagea Byelusnova, then a girl of 16. She bore him four children -- of whom only a son, Zharko, survived.

After numerous further adventures, Tito finally returned to Zagreb in September 1920, found work as a machinist and joined the new Communist Party, which had been founded in April 1919. The Party was outlawed after several attempted assassinations of state officials, and Tito worked underground in a number of Croatian vilages and towns.

In 1924, he became a member of the Croatian regional party leadership and three years later a full-time party organizer as secretary of the Zagreb metal workers' union. During 1927, he was arrested and sentenced to seven months' imprisonment, but released pending appeal.

In February 1928 in a reshuffle of the Croatin leadership following Stalin's victory over Trotsky in Moscow, Tito was named party leader in Zagreb. Six months later, however, he was arrested and charged with membership in the illegal party, disemination of Communist propaganda, and illegal possession of bombs and firearms.

He was sentenced, after a dramatic trial, to five years in prison -- which he served. Among his cellmates was a Belgrade Communist writer and painter, Mosha Pijade -- who remained Tito's chief ideological adviser and theoretician until Pijade's death in 1957. During his imprisonment, Tito was divorced by his first wife, then safely in Moscow.

Released in March 134, he spent nine months organizing the Party in various areas of Yugoslavia, then departed for Moscow, already a member of the Yugoslay Central Committee and inner Politburo. He served in the Soviet capital for more than a year as chief of the Yugoslav desk of the Communist International, and was known to such colleagues as Georgi Dimitrov and Plamiro Togliatti as "Commrade Walter." As a Comintern agent, he spent the next four years roving across Europe -- organizing, among other things, the transport of Communist volunteers for the International Brigade in the Spanish Civil War.

At the end of 1937, Tito was summoned to Moscow and informed by Dimitrov that he had been "provisionally" named General Secretary of the the Yugoslav Communist Party. He never relinquished the title.

Tito acceded to the post in uneasy circumstances. His predecessor had been purged by Stalin together with nearly all the other Central Committee members. Tito's first independent act as secretary general was to insist on local financing of the party rather than Moscow's subsidies. He also surrounded himself with young men, all in their 20s, that included his key lieutenants, Edward Kardelj, Milovan Djilas and Alexander Rankovic. But Tito loyally supported the Hitler-Stalin pact.

However, when the Nazis invaded Yugoslavaia on April 6, 1941, and the Soviet Union on June 22, 1941, Tito and his party assumed new roles: organizers of resistance, under the famous slogan, "Death to Fascism, Freedom to the People!" At a Central Committee meeting on June 27, held in the Belgrade vila of a liberal newspaper publisher, Tito was appointed military commander and the Party Poliburo transformed into a General Headquarters of National Liberation Partisan Detachments. At the end of August, Tito moved to the mountains of western Serbia to direct the Partisan war.

There followed 3 1/2 years of fierce battles and mutual slaughters in which about 1.5 million Yugoslaves -- one-tenth of the population -- lost their lives. It was not a simple Yugoslav-vs-German war. There were, in addition to the German and Italian occupation armies, native pro-Axis and extreme nationalist forces. In Croatia, an "Independent State" was ruled by Ante Pavelic's fanatical Ustashi. In Serbia, General Milan Nedic presided over a Petain-type collaborationist regime. Both these regimes had their armies, and there were paramilitary formations of more extreme groups as well.

Moreover, there existed an authentic Serbian resistance movement led by the famous royalist Gen. Draza Mihajlovich. Several attempts to unite them with Partisans foundered on mutual distrust. In contrast to Mihajlovich. Tito pressed for constant action against the Axis forces, no matter what desperate reprisals were taken against the Yugoslav population.

Perhaps the greatest advantage for Tito's forces was that -- alone among the contending Yugoslav forces -- the Partisans rejected narrow nationalism and preached "Brotherhood and Unity" of all ethnic groups.

In all, the Axis was compelled to mass more than 350,000 troops -- including 14 German divisions -- against the Partisans. Tito's force at the height of the war numbered about 120,000. The Partisans, however, benefited greatly by seizing the lion's share of the arms and supplies surrendered by the 10 Italian divisions in Yugoslavia in September 1943, when Italy changed sides.

Decisive for later developments was the fact that the Partisans received virtually no aid from the Soviet Union, but eventually a great deal from the Western Allies. A British military mission joined the Partisans early in 1943, and within a year London ceased supplying Mihajlovic and was giving all-out aid to the Partisans.

On Nov. 29, 1943, while Roosevelt, Churchill and Stalin were meeting at Tehran, the Partisans' "anti-fascist national liberation front" proclaimed the deposition of the monarchy, and named Tito "Marshal of Yugoslavia" as well as head of a new National Committee or provisional government. In a long series of maneuvers and negotiations, climaxed by the Yalta Conference of February 1945, Tito obtained full Allied recognition of his government at the price of temporarily accepting two non-Communists in the Cabinet. King Peter II never returned to Yugoslavia. Tito served a prime minister until 1953, afterward under a new Consitution as president of the republic. The 1963 Constitution made him, in effect, president for life. t

With the liberation of Belgrade by the Soviet Army in October 1944, the Communist revolution in Yugoslavia began. For nearly four years, Tito seemed the most militant, sectarian and anti-Western of Stalin's disciples.

Tito nationalized Yugoslav industries, collectivized agriculture, unleashed the dreaded UDBA (security police) against political opponents, shot down Western planes, aided the Communist rebels in the Greek Civil War, and kept relations with Italy at a fever pitch over Trieste. Mihajlovic was captured, tried and shot; Aloysius Cardinal Stepinac of Zagreb was tried and imprisoned; nearly 1 million Yugoslavs fled the country between 1944 and 1947. Belgrade became the seat of the new Communist Information Bureau (Comiform), successor to the old Comintern, which had been officially dissolved in 1943.

Then, in the winter and spring of 1947-48 came the crisis that won Tito the abiding respect of his non-Communist countrymen and made "Titosim" a part of the world's political lexicon. The paranoid Stalin became suspicious of plans by Tito and Dimitrov of Bulgaria for a "Balkan Federation," and of Yugoslav designs on Albania (whose Partisan movement had been organized by Vukmoanvic-Tempo and largely controlled by Tito).

The Yugoslavs resented Soviet economic exploitation through "joint companies" and were critical of Soviet compromises at their expense on the Trieste issue during the Paris negotiations for the Italian Peace Treaty of 1947. The Soviet and Yugoslav secret police spied on each other. There was, in addition, a strong opposition within the Yugoslav Party, led by Andreas Hebrang, which regarded Tito's economic policies as unrealistic, and which counted on Soviet support.

Tito sent two missions to Moscow in an attempt to compose the quarrel, but on March 27, 1948, a letter signed by Stalin and Molotov charged Tito, Djilas Kardelj and colleagues with a variety of ideological heresies and grimly warned that "the political career of Trotsky is not uninstructive." (Trotsky had been murdered by Soviet agents in Mexico in 1940). At a Central Committee meeting on April 12, Tito offered to resign but his lieutenants rejected the offer and prepared to defy Stalin. Rankovic's UDBA rounded up about 14,000 pro-Stalinists, including Hebrang. General Jovanovic, the wartime chief of staff, was shot near the Romanian border.

On June 28, 1948, the Cominform announced the expulsion of Yugoslvia. Soon afterward Soviet and satellite leaders began denouncing Tito as a "fascist" and "murderer," while attempting to undermine his rule by subversion and economic blockade. In the other East European Communist states, Stalin settled scores with a host of "national Communist" leaders, now charged with "Titoism."

Tito's response was a gradual turn toward the West. In May 1949, the Yugoslav-Greek, frontier was sealed, an action that brought a speedy end to the Greek Civil War; in February 1953, a "Balkan Pact" was signed with Greece and Turkey, although it later became a dead letter.

In October 1954, the Trieste dispute was settled with Italy keeping the city and Yugoslavia most of the hinterland. But even before the settlement, Tito turned toward the emerging nations of Asia and Africa in an effort to break out of diplomatic isolation. With Nehru of India and Nasser of Egypt, Tito sought to mold new nations into an independent "nonaligned" force.

His efforts bore fruit in the first summit conference of Third World leaders in Belgrade in 1961. As time went on, he continued to place even greater emphasis on his nonaligned policy which he incorporated into the Yugoslav constitution as the binding course of his successors.

For more than a decade, the Yugoslavs were a major force in the nonaligned movement with Tito becoming its senior statesman. Yet, despite his great prestige and reputation his direct influence at the last nonaligned summit in Havana in 1979 declined as the movement came under the sway of a more radical and openly pro-Soviet group of countries led by Cuba's Fidel Castro.

Until his death, Tito remained a committed Marxist-Leninist, albeit one who did not want to be a member of the Soviet bloc. Neither did he want to lead his country toward political pluralism and into the community of West European nations. As a result, his nonaligned foregin policy course was in fact the only viable option open to Yugoslavia -- a safety net in his East-West balancing act.

For Tito, whose talents and ambition by far exceeded the size and strength of his country, there were other reasons for his policy. Early on, he had come to the conclusion that the importance of superpowers in world affairs wooul inevitably decline and that the realative importance of the Third World would rise. And he wanted to ensure his place in history not only as a man who precipitated ideological changes in the Communist movement but also as a leader who helped create a new international environment.

In the years since Stalin's blockade of Yugoslavia, Tito received massive economic and military aid from the West, principally from the United States.

Tito's skillful diplomacy prompted a distinguished former U.S. ambassador to Belgrade to comment privately, "His view of the United States is that of a milk cow, not a bull -- all teats and no horns." A senior Soviet diplomat privately described his country's relations with Tito's government as "cordial and insincere."

But Western aid and influence, combined with Soviet intransigence, led Tito and his colleagues to wide-ranging revisions of Soviet communism. In 1950, Tito proclaimed a new system of "workers' self-management," which gave a significant role in economic enterprises to workers' councils. In 1954, agriculture was decollectivized and in the next years Yugoslavia opened her borders to large-scale tourism.

Continued reforms were introduced, with considerable success, in an effort to decentralize the economy and fit it into the world markets.

Further reforms in 1965 became a watershed in Yugoslavia's history. Tito opened the borders to Yugoslavs, permitting them to leave, and abandoned the stifling command economy in favor of "market socialism." The reforms had an invigorating impact on the country and brought about a dramatic increase in living standards.

The opening of Yugoslavia's borders coincided with Western Europe's economic boom and a sharp demand for labor. Millions of Yugoslavs joined a human wave from southern Europe surging toward the industrial centers of the north. In the 1970s, roughly one million Yugoslavs were temporarily employed in Western Europe at any given time, sending home more than $2 billion annually.

Moreover, Yugoslav businessmen and tourists fanned out all over the world. In August of 1976, for example, more than 700,000 Yugoslavs were vacationing in Greece. Tito himself became one of the leading tourists -- paying visits to nearly all countries in the world.

He visited the United States four times: in October 1960; in 1963, when he was one of the last foreign statesmen to meet with President Kennedy; in 1971 for talks with President Nixon and in 1978 for talks with President Carter.

At home, Tito's power was absolute. He had either outlived or pushed aside all his potential challengers. In 1954, he ousted Djilas, his heir apparent who had urged an end to the one-party dictatorship. In 1965, he forced the ouster of then-heir apparent Rankovic, who opposed Tito's decentralization reforms. In the process, he purged and sharply curtailed Rankovic's secret police. Kardelj died in 1979, leaving Tito without any old associates.

The source of Tito's domestic popularity was his fierce insistence on Yugoslavia's independence during the conflict with Stalin and afterward. After Stalin's death in 1953, Tito sought a reconciliation with Moscow, but on his terms. In May 1955, a group of Soviet leaders led by Khrushchev arrived in Belgrade and apologized for Stalin's mistakes -- the beginning of a long on-again, off-again process of Soviet-Yugoslav rapprochement that has lasted to the present.

However, the Hungarian Revolution in 1956, the Sino-Soviet dispute and the fall of Khrushchev in 1964 each in turn complicated the process of reconciliation. The 1968 Soviet invasion of Czechoslovakia was seen by Tito as having upset the balance he created for the country's continued independence and neutrality. Tito's response was a system of territorial defense involving the entire society, the same concept, he said, that helped him mobilize the people to "fight to defend their independence and liberty" during World War II.

Yugoslavia also strongly condemned the 1979 Soviet invasion of Afghanistan. Coming as it did in the twilight of Tito's rule, the Soviet action appeared to have ominous implications for post-Tito Yugoslavia. Over the years, Yugoslavia has vastly expanded its trade with the Soviet Union and other East European countries without joining the bloc.

At the time of his death, Yugoslavia occupied a special position in Europe -- close to the Soviet bloc, yet not part of it; still strongly affiliated with the Third World yet on good terms with most Western countries. Tito's personal diplomatic skill was largely responsible for the success of this unique balancing act.

In the first years of Communist rule, Tito lived modestly in the Dedinje section of Belgrade; but as the years passed he adopted a regal life-style unmatched by any of the crowned heads to Europe, spending most of his time at his private island of Brioni or at one of his 17 castles and hunting lodges.

In 1952, having divorced his second wife, Herta, he married the dark, beautiful former partisan Jovanka Budisavljevic, than in her early 20s. Jovanka vanished from public view in 1977 after angering Tito for unknown reasons. He subsequently was rumored to have established a liaison with an opera singer nearly 50 years his junior.

Sir Fitzroy Maclean, who led the British Military Mission to the Partisans during the war and remained one of Tito's closest Western friends, drew this portrait of the old marshal.

"With the years and with the experience they have brought, Tito's outlook has widened and become less rigid . . . His sense of humor, always a saving grace, has become still stronger. As a man, he has become calmer, mellower, less flamboyant and more even-tempered: less of a dictator and more of a human being. But he has lost none of his basic toughness and shrewdness . . .

"There is a saying in the Balkans that behind every hero stands a traitor. The difficulty, as often as not, is to determine which is which . . .

"Take Tito himself. Seen from one point of view, he can be represented as a traitor to his king and country, as the agent of a foreign power, who ultimately betrayed even that foreign power. Seen from another, he appears as a national hero twice over."