The world has caught only fleeting glimpses of the savage Soviet conquest of Afghanistan. The television cameramen have been barred. But from secret intelligence reports and eyewitness accounts, I have pieced together the story.

The Soviet version -- that its troops were "invited" into Afghanistan -- is a hideous lie. The Afghans are a ruggedly independent, fiercely nationalistic people, accustomed to few restraints, wary of strangers. Down through the centuries, they have resisted the controls of government.

They could not ignore, of course, the Soviet bear on their northern border.

They maintained strong ties with Moscow, accepted Soviet aid and sent people to Russia for schooling.

Early in the 1970s, the Central Intelligence Agency noted that "the Soviet Union gives ideological indoctrination to Afghan students and military officers trained there." But the communist fever never spread among the staunch Moslems of Afghanistan. In fact, the Soviets couldn't even control the few Afghan communists, who split into loose, rival parties called Khalq and Parcham. The latter was described by the CIA as "an amorphous Moscow-oriented communist political grouping," without any popular support. One of its leaders was Babrak Karmal, who has now been installed by the Soviets as the puppet ruler.

The subversion of Afghanistan began in 1973 while King Zahir Shah was in London for medical treatment. His cousin Mohammad Daoud declared the monarchy at an end and designated himself as the head of a new democratic republic.

This didn't particularly upset the king, who had wanted to abdicate anyway. In the same spirit, members of his family renounced their royal titles, and many continued to serve in the government.

But Daoud's coup, according to the CIA, was "led by left-wing military officers." As their share of the spoils, "Afghan leftists, although relatively few in number, were given a significant role in the government." The CIA also warned that "many of the leftist officials were said to be affiliated" with the pro-Soviet Parcham faction.

Not long afterward, related the CIA, Daoud "began quietly to dismiss some of the leftist." He was "suspicious of the left's ties to the U.S.S.R." and "uneasy about its relative cohesiveness."

Yet despite "Daoud's distrust of pro-Soviet domestic elements," the CIA speculated, he was unlikely to let this "damage Kabul's good relations with Moscow, which stem from the Soviet Union's geographical proximity and Afghanistan's long-standing dependence upon Soviet military and economic aid. aThis dependence of Moscow also has kept Daoud from moving more rapidly and harshly against leftists at home."

But the Kremlin, apparently, was not so easily appeased. With reported Soviet connivance, the rival Khalq and Parcham factions formed an alliance and seized the government. Daoud was murdered on the spot along with members of his family. The Soviet assistance, according to reliable reports, included the murder of a recalcitrant communist leader by a KGB agent.

Khalq party leader Nur Mohammad Taraki assumed the presidency, with Hafizullah Amin as foreign minister. The Soviet favorite, Parcham faction leader Karmal, had to settle for deputy-prime minister.

During the intrigues and purges that followed, Taraki banished the Parcham heavies to diplomatic posts. Karmal wound up as the Afghan ambassador to Czechoslovakia. A few months later, the Parcham diplomats were summoned back to Kabul. They assumed that Taraki intended to elinate them entirely. So they rifled the safes of their various embassies and escaped with an estimated half million dollars. Karmal fled along with his mistress to West Germany. But he soon returned under Soviet protection to Pargue.

Taraki, meanwhile, dropped by the Kremlin for consultations. He conspired with the Soviets to knock off his prime minister, Hafizullah Amin, as the scapegoat for Afghanistan's mounting troubles. But the plot leaked to Amin, who confronted Taraki. In an ensuing gun battle, Taraki was cut down.

Amin was a vain, ruthless man who alienated the populace. He once responded to a report of the resistance to his rule, according to one account, by declaring with a shrug: "The state only needs four million people." The population at the time was 17 million.

The Russian bear swallowed Afghanistan in one gulp. The villainous Amin, who had ruled by the gun, died by the gun. To replace him, the Soviets installed Karmal.

Footnote: My associate Howard Rosenberg has confirmed the CIA reports through Afghan exiles, who receive regular messages from insurgent leaders. The messages are carried by couriers across the mountains into Pakistan where the word is quickly flashed to supporters around the world.