This document explores the use of QR codes in libraries and learning. It begins by providing examples of where QR codes currently appear, such as in newspapers, magazines, books, food packaging, clothing, and tattoos. It then explains that QR codes can be scanned using the camera on a smart mobile device. The document considers how QR codes could be used in libraries to provide supplementary material for books, information about events and services, and to facilitate scavenger hunts and learning activities. It concludes by providing resources for creating and reading QR codes.