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.