Since the rise of the smartphone, apps have become entrenched in billions of users' daily lives. Accessible across phones and tablets, watches and wearables, connected cars, sensors, and cities, they are an inescapable feature of our current culture. In this book, Gerard Goggin provides a comprehensive and authoritative guide to the development of apps as a digital media technology. Covering the technological, social, cultural, and policy dynamics of apps, Goggin ultimately considers what a post-app world might look like. He argues that apps represent a pivowtal moment in the development of digital media, acting as a hinge between the visions and realities of the “mobile,” “cyber,” and “online” societies envisaged since the late 1980s and the imaginaries and materialities of the digital societies that emerged from 2010. Apps offer frames, construct tools, and constitute “small worlds” for users to reorient themselves in digital media settings. This fascinating book will reframe the conversation about the software that underwrites our digital worlds. It is essential reading for students and scholars of media and communication, as well as for anyone interested in this ubiquitous technology.