Microelectromenchanical systems (MEMS) is a revolutionary field that adapts for new uses a technology already optimized to accomplish a specific set of objectives. The silicon-based integrated circuits process is so highly refined it can produce millions of electrical elements on a single chip and define their critical dimensions to tolerances of 100-billionths of a meter. The MEMS revolution harnesses the integrated circuitry know-how to build working microsystems from micromechanical and microelectronic elements. MEMS is a multidisciplinary field involving challenges and opportunites for electrical, mechanical, chemical, and biomedical engineering as well as physics, biology, and chemistry. As MEMS begin to permeate more and more industrial procedures, society as a whole will be strongly affected because MEMS provide a new design technology that could rival--perhaps surpass--the societal impact of integrated circuits.