Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online.Printed electronics is a set of printing methods used to create electrically functional devices. Paper has been often proposed to be used as substrate but due the rough surface and high humidity absorption other materials such as plastic, ceramics and silicon has been applied more widely. Several printing processes have been piloted and printing preferably utilizes common printing equipment in the graphics arts industry, such as screen printing, flexography, gravure, offset lithography and inkjet. Instead of printing graphic arts inks, families of electrically functional electronic or optical inks are used to print active or passive devices, such as thin film transistors or resistors. Printed electronics is expected to facilitate widespread and very low-cost, low-performance electronics useful for applications not typically associated with conventional high performance (i.e., silicon-based) electronics, such as flexible displays, smart labels, decorative and animated posters, and active clothing.