STORM FROM THE EAST: From Genghis Khan to Khubilai Khan By Robert Marshall (BBC Books, $305) NEARLY 800 years later we look back in astonishment at the achievements of the Mongols, history's greatest terrestrial empire builders. Their empire's foreign adventures far exceeded even those of Alexander the Great. The human suffering caused by the Napoleonic wars seem to pale into relative insignificance compared to the enormity of the Mongols' brutality. This was an empire that at the zenith of its power in the 13th century controlled a land mass reaching from the banks of Hungary's river Danube eastward to northern China. On today's map that vast area includes most of eastern Europe, the former Soviet Union, Iran, Afghanistan, northern China (including the expanses of central Asia now a part of China), as well as the Korean peninsula. Never before, and never since, has the Mongols' imperial achievement been rivalled. Like a swarm of locusts they consumed vast territories, often at an extraordinary cost in human lives; according to Iranian researchers the capture of Baghdad in 1258 is alone estimated to have cost the lives of anywhere between 800,000 and two million people. How the Mongols succeeded in uniting the tribes of the central Asian steppes, and forging these disparate, independent peoples into the single united Mongol nation that led to China's Yuan dynasty is the theme of Robert Marshall's book. Even though the Yuan era was short-lived (1279-1368) its influence, largely Mongol, is beyond dispute in Chinese history. The Mongols brought Islam to China, greatly influencing that country's power structure, its architecture and visual arts. Even when the Yuan dynasty was displaced by the Ming, Mongol influence continued to shape Asian history. It was a descendant of Genghis Khan called Babur who, in the 16th century, fled to northern India and founded that nation's great Moghul empire. Robert Marshall is a senior producer for the BBC and develops his theme around the roles played by Genghis Khan and his successors. Although a by-product of the television series entitled Storm from the East, and presumably largely based on the scripts as broadcast, the book is admirable in its own right. Readable, clear, concise and excellently illustrated it is a credit to the BBC's growing and laudable wish to publish as well as broadcast. Genghis Khan grew up in the harsh nomadic conditions of central Asia, a natural leader who fathered the Mongolian nation and a unifier who brought former tribal enemies to drink out of the same cup. He became a legend in his own lifetime: in 1206 characteristically naming himself Great Khan. Thereafter he was, he said, the ''absolute master'' of all the tribes of Mongolia. The Great Khan's ruthlessness and cruelty struck fear into the minds of all his enemies. An Iranian chronicler minced no words when he wrote: ''As a result of the eruption of the Mongols and the general massacre of people which took place in those days. . . there can be no doubt that if for a thousand years to come no evil befalls the country, yet it will not be possible to repair the damage and bring the land back into the state it was in formerly.'' In his later life Genghis Khan, like any tyrant, was much troubled by the question of his succession. When his eldest son Jochi died (a few months before Genghis' own death) the Great Khan decided that his third son Ogedei should succeed him in preference to second son Chaghadai. In the event a compromise made Ogedei the new Khan and his elder brother Chaghadai became lord chancellor and ruler of great tracts of the steppes. Ogedei ruled for 12 years and was as much an aggressor as his father had been; a hallmark of his reign being the overthrow of the Chin empire in 1234. More the politician than his father, Ogedei plotted with officials of the Sung dynasty in south China until in 1234 he was able to occupy the Chin capital of Kaifeng. Carnage followed with his order that every male member of the Chin dynasty be executed. Ogedei's decision to let his hordes loose against the borders of Europe was even more chilling in its boldness and Mr Marshall devotes a complete chapter to the Mongols versus Europe. As the horde moved westward it consumed all in its path, towns and cities were destroyed with a planned ruthlessness that resembles the modern military strategy of the artillery barrage. Ogedei's commanders followed a brilliant strategy, pushing westwards relentlessly into Russia, Poland and ultimately Hungary. By April 1241, the remnants of the original 50,000 strong Mongol force had travelled over 9,500km and established firm dominanceover much of eastern Europe. It was at that crucial moment, when the decision whether to press further westwards had to be taken, that Ogedei died. At an instant Europe's fate was saved. Ogedei's heir and son, Guyuk, died as his father had with alcohol on his lips, though at the age of only 42. He hardly left any mark on Mongolian history and is chiefly remembered as the first Mongol ruler to meet a European, the Franciscan papal envoy John of Plano Carpini. The meeting in 1246 between Guyuk and the Franciscan marked the first important official contact between east and west. The Mongol attack on Europe led them to be ridiculed and caricatured as barbarian monsters. Contacts between east and west reached another turning point when Guyuk's nephew and heir Mongke met Louis IX's envoy the Flemish monk William of Rubruk, the first European to visit the Mongol capital Qaraqorum. That great city, subsequently destroyed and lost to the sands, was only rediscovered in the 19th century. As Mr Marshall reminds us it was Mongke's brother, Khubilai, who succeeded where all his predecessors had failed. Khubilai was not only a gifted warrior but ''arguably the most learned and most cultured and easily the most sophisticated'' of all of Genghis Khan's heirs. Khubilai's ambition to destroy the Sung dynasty reached its culmination with the death of the last Sung emperor during the fierce sea battle of 1279. As emperor of China Khubilai proved himself an enduring success. A great strategist, an intellectual fascinated by astronomy, a man of the arts and architecture, Khubilai's legacy in China remains evident to this day. Like all empires, that of the Mongols disintegrated. In the 17th century the Mongol peoples began to disperse with those to the north coming under Russian sway and those in the south under China's dominance. Anyone with an interest in Mongolian history will enjoy Mr Marshall's book, both its lucid text and its well-chosen and plentiful illustrations.