Electronic textiles are fabrics that can function electrically like electronics while behaving physically like textiles. They enable computing and digital components to be embedded into fabrics. Early research on smart clothing started in the 1990s for military use, while present research focuses on medical applications integrated into clothing. Current electronic textile technologies include the Zoll life vest and VivoMetrics life shirt that monitor health, while proposed future technologies could make systems waterproof and develop smart textiles for children. Electronic textiles have applications in sensor networks, physical therapy, human protection in hazardous environments, and more. They are flexible, have a large surface area for sensing, can be invisible to others, and allow for cheap manufacturing.