During a recent interview at his home in Colombo, Sri Lanka, Arthur C. Clarke displayed a youthful enthusiasm that belied his 84 years. Clad in a batik sarong and pastel shirt with a dolphin motif, the wheelchair-bound author of "2001: A Space Odyssey" was short of breath and complained that he was tired from meeting "too many Australians at a large party." But he was obviously in high spirits, cracking jokes and showing off memorabilia and a "power wall" of signed photos from a slew of celebrities.

Do you see any signs that the primordial inclinations that led to such devastation and destruction in the 20th century are abating in the 21st?

Well, we can't expect an idyllic world, can we? Looking around us I don't see many hopeful signs of improvement, and technology seems to increase the impact of violence. Given what's going on, I give humanity only a 51 percent chance of surviving this century.