With its comprehensive coverage this handbook and ready reference brings together some of the most outstanding scientists in the field to lay down the undisputed knowledge on how to make electronics stretchable. As such, it focuses on gathering and evaluating the materials, designs, models and technologies that enable the fabrication of fully elastic electronic devices which can sustain high strain. Furthermore, it provides a review of those specific applications that directly benefit from highly compliant electronics, including transistors, photonic devices and sensors. In addition to stretchable devices, the topic of ultraflexible electronics is also treated, highlighting its upcoming significance for the industry-scale production of consumer electronic goods. An unprecedented overview of this thriving area of research that nobody in the field -- or intending to enter it -- can afford to miss.