Science entered the twentieth century with newfound knowledge that our world is composed of fundamental building blocks, atoms and molecules, that are extremely small--approximately a nanometer in any dimension. (The prefix "nano," meaning one-billionth, comes from the Greek word nanos, meaning dwarf) As the twenty-first century begins, science has begun to manipulate these building blocks one at a time, on the brink of constructing nano-sized machines and components that can make many products lighter, stronger, smarter, cheaper, cleaner, and more precise. This new field is called nanotechnology, a word coined by engineer K. Eric Drexler in 1981.

The invention of the scanning probe microscope (SPM)opened a new window into the molecular and atomic realm. With it comes the ability to view individual molecules and atoms, and in some cases to watch their progression as a system evolves. Now that they can be viewed, nanotechnology seeks to take the...