The book is about Arduino programming language and the Arduino Software (IDE), based on Processing. Arduino boards are able to read inputs - light on a sensor, a finger on a button and turn it into an output - activating a motor, turning on an LED, publishing something online. You can tell your board what to do by sending a set of instructions to the microcontroller on the board. Arduino is an open-source electronics platform based on easy-to-use hardware and software. The Arduino software is easy for beginners, yet flexible enough for advanced users. It runs on Mac, Windows, and Linux. Teachers and students use it to build low cost scientific instruments, to prove chemistry and physics principles, or to get started with programming and robotics. Thanks to its simple and accessible user experience, Arduino has been used in thousands of different projects and applications.