Dream topic [About This Issue]

Suppose that, at an early age, you were forced to choose a topic in science or engineering that you would spend your entire career on. To be safe, you might search for the "ideal" research topic-a topic that is immediately understandable by everyone, has inestimable value in the commercial sector, is accessible enough to allow modest progress with reasonable effort, involves interesting science and technology ranging from chemistry to mechanics, and is hard enough that it is highly unlikely that someone will solve the problem and declare the research area dead. This tall order is easily met by the most basic and ubiquitous of physical phenomena: friction.