As the information contained in databases has become a critical resource in organizations, efficient access to that information and the ability to share it among different users and across different systems has become an urgent need. The interoperability of heterogeneous database systems-literally, the ability to access information between or among differing types of databases, is the topic of this timely book. In the last two decades, tremendous improvements in tools and technologies have resulted in new products that provide distributed data processing capabilities. This book describes these tools and emerging technologies, explaining the essential concepts behind the topics but focusing on practical applications. Selected products are discussed to illustrate the characteristics of the different technologies. This is an ideal source for anyone who needs a broad perspective on heterogeneous database integration and related technologies.