The most mysterious, least-known area of man's universe does not lie in the farthest reaches of outer space. Nor is it found in the most remote Amazonian jungle or in the inky blackness of the Mariana Trench. It is located instead in side the human skull, and consists of some 3½ pounds of pinkish-gray mate rial with the consistency of oat meal. It is, of course, the human brain.
The brain is the most important of the body's organs. The heart, after all, is merely a pump; the lungs are an oxygenation system. But the brain is the master control, the guiding force behind all of man's actions. It is the seat of all human thought and consciousness, the source of the in genuity that made it possible for man's ancestors to survive and eventually to dominate their physically more powerful adversaries and evolve into the planet's highest form of life. Everything that man has ever been, everything he will be, is the product of his brain. It is the brain that enabled the first humanoid to use tools and that gives his genetic successors the ability to build spacecraft, explore the universe and analyze their discoveries. It is the brain that makes man man.
But it took man centuries to comprehend that there was a miraculous mechanism in side his head and begin to in vestigate its workings. Aristotle taught his pupils that the brain was merely a radiator or cooling system for the blood; he identified the heart as the organ of thought. Pliny the Elder was one of the first to identify the brain as "the citadel of sense perception." But nei ther he nor generations of scientists who followed him had the knowledge or techniques to explore it. Investigation was also stymied by philosophical obstacles. The brain was considered the seat of the soul; its nature and its workings were considered not only unfathomable but sacrosanct.
Now man has embarked on a great voyage of discovery. In dozens of lab oratories in cities round the world, psychologists, biologists, physicists and chemists, recognizing that what goes on inside the brain cannot be divorced from what goes on outside, in increasing numbers are poking, prodding and analyzing the organ in an attempt to unlock its secrets. Man has split the atom, cracked the genetic code and, in a Promethean step unimaginable less than a quarter-century ago, leaped from his own terrestrial home to the moon. But he has yet to solve the mysteries of memory, learning and consciousness or managed to understand himself.
The brain is the newest and perhaps last frontier in man's exploration of himself. Crossing that frontier could have the same impact on humanity as the discovery that the earth was round. "We are like the Europeans of the 15th century," rhapsodizes one brain researcher. "We're standing on the shores of Spain or Portugal, looking out over the Atlantic. We know that there is something on the other side and that our discovery of exactly what this is will mean that things in our world will never be the same again."