How to make something work in the mud. Our modern world is complex and messy. To be effective, people need to be their own engineers, knowing how to fiddle with technology under adverse conditions. Our students build robots that work even in places like Antarctica.

How to tell what's really going on. The methods of empirical science must be understood by everyone. The ability to discern a real phenomenon and distinguish it from myth is vital. Our students learn to measure the performance of people using technology.

The computer is an amazingly versatile tool that is transforming our world. It's also an intellectual challenge, and computer scientists are concerned with several deep questions.

What can be computed? Early in this century mathematicians and philosophers discovered limits to what any device or human could deduce from consistent rules. This exploration continues today with the study of many apparently simple problems; e.g., discovering the factors that multiply to a given number. The possibility or impossibility of doing such things quickly is a tantalizing question with significant practical implications for such things as cryptography.

What is intelligence? A computer's beating the world chess champion is a side-show of the far more fascinating and important study of the nature of intelligence. Computers can simulate many things and the behavior of humans and other life forms is one of the most important. Today, computer scientists in alliance with psychologists and biologists are unraveling some mysteries and, along the way, producing devices that listen, see, and act in the real world.

Is there a better way to build computer systems? Despite the evident success of Microsoft's operating systems and the C programming language, there are many alternatives worth exploring, especially as we extend the purposes and environments of computers and networks. At the extreme, the uses of quantum effects, microbiology, and evolution are being explored.

How does computing fit into the world? More than a calculator, the computer is becoming the interface between people and their world. Computers mediate between me and my car's brakes as well as between me and my E-mail correspondents. Computer scientists and social scientists are working to chart and predict the impact of computers on the intersecting worlds of work, entertainment, and society. To do this, they must answer new questions, not about computers, but about us.

Given these lofty pursuits, why should an 18-year-old intent upon making his or her fortune seek a degree in computer science? Many people have done very well without such a degree, but the dirty little secret behind industry's voracious appetite for programmers is that older programmers with obsolescing knowledge are being rejected--now that they have fixed all those Y2K bugs. Anyone seeking a lifetime career needs to prepare themselves with a lot of basic knowledge and the ability to learn new things. A well-designed college education can do that.

Good computer-science programs include liberal arts, mathematics, and experimental science. The computer-oriented studies are focused not just on programming skills but on the things a person should know to prosper in a computing-intensive world: the potential and the limits of computing devices, matching solutions to problems, and the ethics of information use. More generally, we impart basic skills--how to judge what you know, how to learn what you need to know, and how to communicate--with the added feature that one can use computers and networks to help.

In fact, computer-science departments are experiencing growing interest from today's best science students. Carnegie Mellon's applications have more than doubled in the past five years, and incoming freshmen computer scientists have extraordinary credentials. Also, the percentage of women has increased dramatically--a sign that computer science isn't just for nerds anymore.

Some computer scientists are skeptical about the benefits of computers or worried about their misuse. Those who regard computers as a potential enemy can and should be eager students of computer science, too. Willy-nilly, all of us are becoming computer users and it will be more fun and less worrisome if we know what it's all about--that is one of the great intellectual adventures of our era.

As programmed digital devices continue to shrink in size and cost, many of us predict that the computer per se will disappear just as the electric motor disappeared into hundreds of niches in our homes and automobiles. Then we will have a science named after an artifact no one sees. But the essence of the science will still be there, and those who study it will be rewarded not just with riches but with understanding.

James H. Morris is dean of Carnegie Mellon University's School of Computer Science.