The strategic importance of information systems is now widely accepted, and over the last three decades these systems have received considerable investment. Systems have evolved from file systems, through database systems, to the emergence of Management Information Systems (MIS) and – more recently – Executive Information Systems (EIS). With the advent of each new form of the technology there has been a need to redesign and re-implement existing systems. Hence the dramatic increase in the amount of resources put into the area of reengineering. Reengineering involves the re-design of an existing Information System, whilst utilising as much of the existing system as possible. This text takes a practical approach to re-engineering existing systems and looks at data integration, and focuses on proven methods and tools for: •the conversion of hierarchical or network database systems into relational database technology, or from relational to object-oriented and XML databases •the integration of database systems and expert systems to produce MIS and EIS systems Taking a very practical approach, the book describes in detail database conversion techniques, reverse engineering and forward engineering, and re-engineering methodology for information systems, offering a systematic software engineering approach for reusing existing database systems built with "old" technology. Many examples, illustrations and case studies are used, making the methodology easy to follow. An Instructor’s Guide is available on website: www.springer.com/1-84628-382-5 for lecturers.