This paper introduces a novel silicon-based technology that offers a physically transient form of electronics, designed to gradually disappear over time in a controlled and programmed manner. Unlike conventional silicon electronics, which remain functionally and physically invariant, this technology creates applications such as active implants that exist for medically useful timeframes but then completely dissolve and disappear via resorption by the body. The authors present a comprehensive set of materials, manufacturing schemes, device components, and theoretical design tools for this type of complementary metal oxide semiconductor (CMOS) electronics, along with four different classes of sensors and actuators. The technology is based on silicon nanomembranes (Si NMs) and uses magnesium (Mg), magnesium oxide (MgO), and silicon dioxide (SiO2) for conductors, dielectrics, and semiconductors, respectively. The materials are encapsulated in silk, which is both water-soluble and enzymatically degradable. The dissolution process is driven by hydrolysis, and the authors provide detailed models and experimental results to demonstrate the transience of the materials. The technology is demonstrated in various applications, including medical monitors that fully resorb when implanted into the human body and communications systems that dissolve when exposed to water. The paper also includes in vivo experiments showing the biocompatibility and bio-resorption of the transient devices.This paper introduces a novel silicon-based technology that offers a physically transient form of electronics, designed to gradually disappear over time in a controlled and programmed manner. Unlike conventional silicon electronics, which remain functionally and physically invariant, this technology creates applications such as active implants that exist for medically useful timeframes but then completely dissolve and disappear via resorption by the body. The authors present a comprehensive set of materials, manufacturing schemes, device components, and theoretical design tools for this type of complementary metal oxide semiconductor (CMOS) electronics, along with four different classes of sensors and actuators. The technology is based on silicon nanomembranes (Si NMs) and uses magnesium (Mg), magnesium oxide (MgO), and silicon dioxide (SiO2) for conductors, dielectrics, and semiconductors, respectively. The materials are encapsulated in silk, which is both water-soluble and enzymatically degradable. The dissolution process is driven by hydrolysis, and the authors provide detailed models and experimental results to demonstrate the transience of the materials. The technology is demonstrated in various applications, including medical monitors that fully resorb when implanted into the human body and communications systems that dissolve when exposed to water. The paper also includes in vivo experiments showing the biocompatibility and bio-resorption of the transient devices.