Why are people so interested in dinosaurs? Why are we so fascinated by these giant vanished creatures from the past? There are many reasons, but the I believe most compelling is that the dinosaurs confront us—directly and unavoidably—with the reality of extinction.

This has always been so. In the late 1700s, when giant animal bones were first dug up in Europe, they caused a crisis among scientists of the time. What could account for these bones? What animals did they represent? At first, scientists argued that the bones were the remnants of gigantic versions of animals now represented in smaller, contemporary forms. Most scientists thought that this explanation must be true, since God had created the world in the Biblical seven days—and God would never allow any of his creations to become extinct. The natural world at that time was essentially seen as a static, unchanging world. Individual animals might die, but whole species did not. Therefore it followed that these old bones could only represent variants of animals still alive.

But with further study, that early view proved unsupportable. These bones were not gigantic lizards or elephants. And in 1805, Baron Georges Cuvier, the most influential anatomist of his day, reluctantly concluded that the bones represented creatures that had become extinct. Cuvier believed that the extinctions had occurred as a result of world-wide catastrophes, akin to Noah’s flood. His theory, called Catastrophism, was hotly debated—and widely ridiculed—for decades to come.

Although Cuvier’s daring intellectual leap led to the eventual acceptance of extinction, his belief in catastrophe fared less well. The systematic study of geology in the nineteenth century led instead to a new doctrine, called Uniformitarianism, which argued that the earth changed gradually, and that extinctions had occurred slowly over time.

When Darwin proposed his theory of evolution in 1859, he built upon these ideas of gradual change. In the new Darwinian picture, there was little room for violent catastrophe. Indeed, in the post-Darwinian world, Catastrophism seemed to reflect the emotional turmoil of Cuvier and his pupil Agassiz, men who opposed evolution for religious reasons, and who were obliged to invoke violent upheaval to fit their beliefs to the geological record. For the next century, Catastrophism languished in the intellectual museum drawer reserved for Curious Outmoded Beliefs.

This was still the case when I was a university undergraduate, in the 1960s. As a student I studied evolution; it excited my imagination; and in fact my novel The Andromeda Strain was suggested by a footnote in George Gaylord Simpson’s scholarly text, The Major Features of Evolution. In those days, Simpson was an emeritus professor at Harvard, and on warm days he could be seen sitting on the steps of the Agassiz Museum, sunning himself like a wise old lizard. (I never had the nerve to go up and speak to him.) Simpson had pioneered the use of statistics in paleontology, and was one of the scientists leading the study of evolution into more rigorous mathematical analysis. So was my own professor, William Howells, who used complex computer programs to study of human evolution, and encouraged his students to do the same.

Even back in the 1960s, there was plenty of debate about evolution. It was understood to be an inherently contentious subject; when Louis Leakey gave a lecture at Harvard in 1963, scholars in the audience leapt angrily to their feet, shouting at him, and stalking red-faced from the auditorium. Feelings ran strong then—and they still do.

Many surprising developments in evolution have occurred in the decades since then, but to my mind none more unexpected than the sudden resuscitation of Baron Cuvier and his sleepy old doctrine of Catastrophism. After two hundred years of ridicule, catastrophe is again a topic of controversy, the subject of magazine articles and television specials. The immediate reason is the speculations of Luis Alvarez and his team on the possiblity that a metoric impact caused the Cretaceous extinctions that killed the dinosaurs. But underneath it all lies a deeper and peculiarly modern question—what makes any species become extinct?

As I began to write this novel, I found myself returning unexpectedly to the concerns of my undergraduate studies thirty years ago. Back then, evolution was so controversial that one quickly learned to write cautiously, justifying even the mildest statement with scholarly footnotes. If anything, evolution is more controversial today. And in its modern formulations, evolutionary theory is forbiddingly difficult, and frequently counter-intuitive. In The Lost World, I have been able only to touch on some of the most interesting trends in current scientific thinking, and to hint at the complexities of thought that lie beneath the surface of every point of view.

And, of course, there is an ever-present theological aspect. In an early draft of the novel, Ian Malcolm, heavily sedated with morphine, expressed his belief about the choice God had made in creating the world. Malcolm said that in his view, God might have created a perfect world of immortal creatures, where nothing ever changed. Such a world would be like an artist’s painting, perfect just as it was at the instant of creation, and never in need of change.

But evidently God had decided on a different sort of creation. Because instead, God had created a world where change occurred—where creatures were born, reproduced, and died. Where new generations took over, and replenished the earth. And therefore, Malcolm concluded, God must have believed in the importance of change. Not easy or frivolous change, because God’s world was inherently conservative, and it resisted change. But nevertheless, hard-won change did occur. So the fact of change was central in our God-given world.

But, Malcolm continued, nobody seemed to like that, or to accept it willingly. There were some people who refused to change anything for thousands of years. And other people who wanted to change every six months, like fashions. Either way was too easy, Malcolm said. Because God had created a world that was tougher than that. God’s world forced hard choices, and did not permit easy answers.

As originally written, Malcolm’s long tirade put the others to sleep. I cut it late in my revisions, because it just didn’t seem to fit. But I always liked the speech. And I remain convinced that the world we are born into is a world of controversy, and that it behooves us to respect our adversaries, and to honor them as expressing another aspect of God’s will.

Because in the end, evolution is a profound mystery. Life is a profound mystery. And we are fools if we forget that and think, even for a moment, that we know it all.