Aimed at undergraduates, graduate students, and practicing engineers, this textbook covers the essential principles of organic electronics from its fundamental concepts through to describing archetype devices that exploit the unique properties of the immense materials family of organic semiconductors in use today. While the book assumes some familiarity with conventional semiconductors and devices, it does not require extensive expertise, as essential background material is provided in the text. Furthermore, a background in chemistry is not required. The first four chapters introduce the basic physics of organic semiconductors, starting with materials structure, then introducing the fundamentals of their optical and electronic properties. The ensuing chapters cover specific devices and how to make them, the challenges that yet remain to achieve even higher performance, and their potential applications. The device chapters cover organic light emitting diodes (OLEDs), photodetectors and solar cells, and thin film transistors. The book closes with a chapter on the challenges and opportunities that still confront this rapidly growing field.