Nanotechnology, the application of the science of the very small, is an exciting field that is enabling solutions in alternative energy, electronic devices, medical diagnostics and therapeutics. Engineers are finding that when things are very small, interesting phenomena can occur simply due to their physical size. Examples of these effects include quantum confinement in nanoparticles, which are making electronic display screens with higher color purity as well as tumor and disease diagnostics for cancer detection, and next-generation electronic devices made from low-dimensional materials, which have electronic properties that have the promise to have higher performance than today's silicon devices. However, this is not the only type of nanotechnology. Engineers are also finding that when things are very small, they can be arranged into systems of remarkable spatial and functional complexity, even if their behavior is explainable by classical physics. Examples include integrated circuit design and fabrication, the highly integrated systems in today's handheld electronics and smartphones, and applications in the most advanced digital movie theaters, where image projection is accomplished through the coordinated microelectromechanical action of the millions of tiny moving mirrors on a silicon chip.