When Columbus, Cortes, Pizarro and other European colonists arrived in the New World five centuries ago, why weren't they driven into the sea by thousands of native warriors on horseback brandishing guns and carrying epidemic diseases?

Why didn't rhino-mounted Bantu warriors swarm north to decimate horse-mounted Romans and create an empire that spanned Africa and Europe?

These and many other questions are answered persuasively in Jared Diamond's fascinating new book, Guns, Germs, and Steel (W.W. Norton, 1997). It's the first explanation of history I've seen that gets at the key question of why Europeans and Asians, came to control most of the world, rather than Africans, Native Americans or other people.

Diamond's primary thesis is that there's no inherent superiority among any racial or ethnic groups, and that the often-tragic failure of other races to resist expansion by other peoples was largely a matter of bad luck.

He marshals mountains of evidence to suggest that Europeans and Asians achieved dominance because they had an abundance of plants and animals suitable for domestication, and because the east-west orientation of the Eurasian landmass eased the transfer of animals, crops, and technology.

Eurasia had 32 of the 56 prize wild grasses that were candidates for cultivation; no other region had more than six. It was home to 13 of the 14 animals most important to humans.

The Fertile Crescent, an area of Southwest Asia occupying portions of what are now Iraq, Jordan, Syria and Turkey, had six of the eight "founder crops" and four of the five most important domesticated mammals—the cow, goat, pig and sheep.

It's no surprise that the Fertile Crescent produced prodigious amounts of food and that the earliest known examples of many kinds of human development began there about 11,000 B.C. People outside Eurasia, and especially outside the Fertile Crescent, were at a big disadvantage because there wasn't much for them to work with. Few of the world's 200,000 wild plant species have food value to humans. More than 80 percent of the modern world's crop tonnage comes from just 12 species: banana, barley, corn, manioc, potato, rice, sorghum, soybean, sugar beet , sugarcane, sweet potato and wheat.

"Our failure to domesticate even a single major new food plant in modern times suggests that ancient peoples really may have explored virtually all useful wild plants and domesticated all the ones worth domesticating," Diamond writes.

Domesticated animals furnished fertilizer, meat and milk. They pulled plows. They helped win wars. Whereas the Fertile Crescent had many, California had no important mammals to domesticate, despite sharing a similar climate.

In fact, North America had no large mammals suitable for domestication other than the llama, and it wasn't widespread. When human hunters arrived in the Americas via the Bering Strait about 13,000 years ago, they apparently killed most of the unwary mammals that would have been suited to domestication.

"About 15,000 years ago, the American West looked much as Africa's Serengeti Plains do today, with herds of elephants and horses pursued by lions and cheetahs, and joined by members of such exotic species as camels and giant sloths," Diamond writes. Soon these species were extinct.

In Europe and Asia, food surpluses allowed some people to specialize in science or art and others to focus their energies on being soldiers. Civilizations grew in the Fertile Crescent and spread to the east and west.

One reason a native cavalry didn't drive Columbus and other European colonialists back into the Atlantic was that there were no native horsemen. The Americas didn't have horses again until Europeans brought them, and the natives didn't get them until they escaped from Spanish explorers.

Rhino-mounted warriors didn't swarm into Europe from Africa because rhinos can't be domesticated. Nor can elephants, hippos, zebras or any of the other African animals that would otherwise make great allies in war. These animals can sometimes be tamed into submission, but their breeding—and hence their genetic characteristics—can't be controlled the way horses can.

Diamond illustrates the enormous competitive advantage enjoyed by societies with horses and guns by recounting how Spanish conquistador Francisco Pizarro used 62 horsemen and 106 foot soldiers to destroy thousands of Inca soldiers on Nov. 16, 1532. In a matter of hours, Pizarro's small band captured the Inca emperor Atahuallpa, leader of America's most advanced state, by panicking the emperor's 80,000 guards.

Disease was even more important than horses or guns in the European subjugation of the Americas and the rest of the world. Diamond estimates that European disease wiped out 95 percent of America's pre-Columbian population. Epidemics spread from tribe to tribe, often well in advance of the Europeans themselves.

Why, instead, didn't Indian epidemic diseases wipe out Europeans?

Epidemic diseases originated in domesticated animals. Measles, smallpox and tuberculosis came to humans from cattle, flu came from pigs and ducks, and pertussis (whooping cough) came from pigs and dogs.

Indians didn't have epidemic diseases or immunities because they didn't have the domesticated animals that gave rise to the diseases.

Besides having good grains, good animals and diseases on their side, Eurasians were blessed with a huge landmass that was oriented east-west rather than north-south like Africa and America.

People could take their crops and livestock long distances to the east or west, because climate tended not to change much along a given latitude. Trade routes eventually opened from Asia to Europe.

North-south migration tended to be vastly more difficult. Abrupt climate changes would render a crop useless, and mean the wrong forage and weather for livestock. African and American civilizations were isolated by mountains, deserts or rainforests and often unable to share in the advances of other cultures that might be as little as 1,000 miles to the north or south.

Natives of Australia, New Guinea and much of the rest of the Pacific suffered because of their isolation, too. Diamond makes a compelling case that traditional lifestyles in New Guinea and Australia, rather than showing a lack of "advancement," as defined by Europeans, were in fact intelligent adaptations to areas with difficult soils and climates and a lack of domesticable animals. A thousand years ago Asia was equal or ahead of Europe in many technologies.

Diamond argues that Europeans later pulled ahead of Asians because Japan and China became inward-looking and stopped trading ideas with other countries. The result, almost by default, was European domination of much of the world until after World War II.

Japan and now China have roared back as economic powers, and for Japan technological innovation has been a key to its enormous strides in recent decades. "Guns, Germs, and Steel" lays a foundation for understanding human history, which makes it fascinating in its own right. Because it brilliantly describes how chance advantages can lead to early success in a highly competitive environment, it also offers useful lessons for the business world and for people interested in why technologies succeed.

The book reminds me that innovation sustains success while complacency leads to stagnation and decline—a lesson I try to keep in mind every day.

In early human history, technological advantages were built on the availability of certain plants, animals and geographies.

In today's emerging information society, the critical natural resources are human intelligence, skill and leadership. Every region of the world has these in abundance, which promises to make the next chapter of human history particularly interesting.