Book excerpt: Flexibility and stretchability of electronics are crucial for next generation electronic devices that involve skin contact sensing and therapeutic actuation. This handbook provides a complete entrée to the field, from solid-state physics to materials chemistry, processing, devices, performance, and reliability testing, and integrated systems development. This work shows how microelectronics, signal processing, and wireless communications in the same circuitry are impacting electronics, healthcare, and energy applications. Key Features: • Covers the fundamentals to device applications, including solid-state and mechanics, chemistry, materials science, characterization techniques, and fabrication; • Offers a comprehensive base of knowledge for moving forward in this field, from foundational research to technology development; • Focuses on processing, characterization, and circuits and systems integration for device applications; • Addresses the basic physical properties and mechanics, as well as the nuts and bolts of reliability and performance analysis; • Discusses various technology applications, from printed electronics to logic and memory devices, sensors, actuators, displays, and energy storage and harvesting. This handbook will serve as the one-stop knowledge base for readership who are interested in flexible and stretchable electronics.