Although mobile devices in libraries have been a hot topic, they are often discussed in the context of affluent populations and academic libraries. The demographics of mobile internet users are much more diverse than this, and the potential for mobile services is correspondingly broad. Chapter 1 discusses who uses the mobile internet. Chapters 2 and 3 discuss examples of current library services aimed at diverse populations which use mobile devices, or could readily be adapted to. Chapter 4 speculates on future possibilities, grounded in existing projects, and provide guidance for librarians looking to develop technological capacity. Wherever possible, the focus of the issue is on services that can be implemented quickly and cheaply.