This book was written to further our collective understanding of the role that the antecedents and consequences of handset upgrades have upon post-upgrade usage of mobile content and services, while simultaneously determining if such findings developed within the world's most advanced mobile market (Japan) could be applied internationally. The three case studies presented in this book explore the antecedents and consequences of handset upgrades from distinctly different perspectives, and include both quantitative and qualitative methodologies. As the world marches beyond its 4 billionth mobile subscriber, the opportunities and benefits inherent in such widespread adoption of mobile and wireless technologies are significant. The contributions and insights discussed here are intended to provide a consolidated body of knowledge upon which further inquiry and concepts can be developed, helping to promote the creation and implementation of more inclusive and more effective mobile solutions throughout the world.