This book has its origins in a painstaking process of research into the practical difficulties that organizations experience in segmenting their markets, research which we initiated in 1992. We discovered that most of the academic work in this domain is prescriptive, with virtually no pragmatic guidelines provided to enable managers to make sense of the confusing array of data and information available to them. So we developed a process, which we worked through with some of the best-known companies in the world, amending the process until it was sufficiently robust to share with a wider audience. The result was the first edition of this book which was launched in 1995. Since its launch, the extensive adoption of our market segmentation process by companies ranging from world leaders in their fields to smaller domestic companies has continuously broadened our knowledge base substantially. This has enabled us to refine the process, improve the guidelines for its implementation, identify where more detailed explanation is required and, at the same time, develop a quick route through the process for those readers who are familiar with the detail and require only a summary of how to implement each step.