Mobile phones seem to have become a ubiquitous phenomenon of the societies of the industrialized nations in the 1990s and the beginning of the 21st century. Even though Japan is not the leading market in terms of penetration rate, it is still considered to be the world's most innovative and advanced mobile communications market. Especially in the field of mobile commerce, Japan is regarded as a role model for markets in other countries and Western firms are trying to learn their lesson from Japan's experience. This book is to provide an introduction to the Japanese mobile communications market from a consumer behavior perspective. Consumers and their behavior and perceptions lie at the heart of the analysis of this book. The goal is to shed some light on the driving forces in the Japanese mobile telephone market, which basically made Japan the leading market in mobile phone technology, as it was the first country in the world to have introduced mobile internet, camera phones and mobile telephony of the third generation. In order to better understand the factors behind Japan's superiority, the market will be scrutinized both from the supply side as well as from the demand side.