This book explores the development of a model (funded by the Agency for Healthcare Research and Quality in 1998) to predict and explain the degree of success of such implementation efforts. This model allows an institution to benchmark its progress towards IHCS implementation and advises administrators where to invest resources to increase the chance of successful implementation. A set of case studies highlights key features of the model; each study describes an attempt by an organization to implement the Comprehensive Health Enhancement Support System (CHESS), a proven IHCS. After examining the success or failure of each particular implementation, the book suggests steps that could have been taken to address weaknesses identified by the model. Investing in eHealth culminates in a set of general guidelines for any health care provider striving to successfully employ the model, and suggests directions for future research.