Information systems are the backbone of many of today's computerized applications. Distributed databases and the infrastructure needed to support them have been well studied. However, this text addresses distributed database interoperability by examining the successes and failures, various approaches, infrastructures, and trends of the field. A gap exists in the way that these systems have been investigated by real practitioners. This gap is more pronounced than usual, partly because of the way businesses operate, the systems they have, and the difficulties created by systems' autonomy and heterogeneity. Telecommunications firms, for example, must deal with an increased demand for automation while at the same time continuing to function at their current level. While academics are focusing on investigating differences between distributed databases, federated databases, heterogeneous databases, and, more generally, among loosely connected and tightly coupled systems, those who have to deal with real problems right away know that the only relevant research is the one that will ensure that their system works to produce reasonably correct results. This volume covers the underlying principles and infrastructures needed to realize truly global information systems. The book discusses technologies related to middleware, the Web, workflows, transactions, and data warehousing. It also overviews architectures with a discussion of critical issues. The book gives an overview of systems that can be viewed as learning platforms. While these systems do not translate to successful commercial realities, they push the envelope in terms of research. Successful commercial systems have benefited from the experiments conducted in these prototypes. The book includes two case studies based on the author's own work. The book should be suitable as a textbook for a graduate-level course as well as a secondary text for a graduate-level course on database or information systems, and as a reference for researchers and practitioners in industry.