This chapter presents the spreadsheet-driven spreadsheeter application development (SAD) methodology for the development of process-centric application systems. The first phase of SAD methodology deals with the problem of identifying enterprise business processes that are essential for the functioning of the organization. The second phase of SAD methodology deals with developing a process model for the business processes identified in the previous phase and involves completing parts I and II of the activity spreadsheet. The chapter then visits the concepts of deductive database (DB) and deductive spreadsheet as a preparatory step. DBs were proposed as an attempt to overcome the limitations of traditional DB systems by incorporating the characteristics features of expert systems. Deductive DB management systems must provide a query-processing system that is able to answer queries specified in terms of views as well as in terms of base predicates.