The article introduces "ionic skin," a new type of stretchable, transparent, and biocompatible sensory sheet that uses ionic conductors instead of electronic conductors to report signals. Unlike traditional electronic skin, which relies on electrons for signal transmission, ionic skin uses ions, enabling it to detect a wide range of stimuli, including deformation, pressure, and touch. The ionic skin is highly stretchable, with a large dynamic range of strain (1% to 500%), and can measure pressure as low as 1 kPa. It is also transparent, allowing it to transmit electrical signals without impeding optical signals, making it suitable for applications such as optical stimulation and continuous surface inspection. The ionic skin is composed of a stretchable dielectric sandwiched between two ionic conductors. When external forces deform the dielectric, the capacitance of the structure changes, allowing the ionic skin to sense deformation. The design of the ionic skin includes a hybrid ionic-electronic circuit, where ionic conductors connect to metallic electrodes outside the active area of the sensory skin. This design allows the ionic skin to be highly stretchable and transparent, with the dielectric and ionic conductors being stretchable and transparent, while the electronic conductors can be made of stiff and opaque metals. The ionic skin is capable of detecting both the location and pressure of touch. It was demonstrated using a sheet of distributed sensors, with four small squares of hydrogel over a dielectric, which in turn lay over a single large layer of grounded hydrogel. A rotational switch connected the four sensors to a capacitance meter, allowing the ionic skin to detect the location and pressure of touch. The ionic skin can resolve the pressure of a gentle touch of a finger (<10 kPa) and continuously measures the level of pressure, unlike traditional on/off buttons that express two states. The ionic skin has potential applications in wearable or implantable electronics, particularly due to its high transparency, which allows it to transmit electrical signals without impeding optical signals. The ionic skin is highly stretchable, transparent, and biocompatible, making it suitable for a wide range of applications, including healthcare and entertainment. The design of the ionic skin is based on the use of ionic conductors, which are highly stretchable and transparent, and can be used in combination with stretchable and transparent dielectrics to create actuators and sensors. The ionic skin is a capacitive sensor, which achieves the highest precision of all electrical sensors, has simple and robust structures, features high sensitivity and resolution, and allows long-term, drift-free sensing even when temperature changes.The article introduces "ionic skin," a new type of stretchable, transparent, and biocompatible sensory sheet that uses ionic conductors instead of electronic conductors to report signals. Unlike traditional electronic skin, which relies on electrons for signal transmission, ionic skin uses ions, enabling it to detect a wide range of stimuli, including deformation, pressure, and touch. The ionic skin is highly stretchable, with a large dynamic range of strain (1% to 500%), and can measure pressure as low as 1 kPa. It is also transparent, allowing it to transmit electrical signals without impeding optical signals, making it suitable for applications such as optical stimulation and continuous surface inspection. The ionic skin is composed of a stretchable dielectric sandwiched between two ionic conductors. When external forces deform the dielectric, the capacitance of the structure changes, allowing the ionic skin to sense deformation. The design of the ionic skin includes a hybrid ionic-electronic circuit, where ionic conductors connect to metallic electrodes outside the active area of the sensory skin. This design allows the ionic skin to be highly stretchable and transparent, with the dielectric and ionic conductors being stretchable and transparent, while the electronic conductors can be made of stiff and opaque metals. The ionic skin is capable of detecting both the location and pressure of touch. It was demonstrated using a sheet of distributed sensors, with four small squares of hydrogel over a dielectric, which in turn lay over a single large layer of grounded hydrogel. A rotational switch connected the four sensors to a capacitance meter, allowing the ionic skin to detect the location and pressure of touch. The ionic skin can resolve the pressure of a gentle touch of a finger (<10 kPa) and continuously measures the level of pressure, unlike traditional on/off buttons that express two states. The ionic skin has potential applications in wearable or implantable electronics, particularly due to its high transparency, which allows it to transmit electrical signals without impeding optical signals. The ionic skin is highly stretchable, transparent, and biocompatible, making it suitable for a wide range of applications, including healthcare and entertainment. The design of the ionic skin is based on the use of ionic conductors, which are highly stretchable and transparent, and can be used in combination with stretchable and transparent dielectrics to create actuators and sensors. The ionic skin is a capacitive sensor, which achieves the highest precision of all electrical sensors, has simple and robust structures, features high sensitivity and resolution, and allows long-term, drift-free sensing even when temperature changes.