What ever the change is, managers should not only design the new shape of their organization but also the path they need to take to get there. With the complexity of the todays organization and the size and type of change needed, expected change should not be straightforward linearly achievable tasks. Also, as we deal with so many aspects of the organization on the technical, social, and human dimensions, no one group should dominate the change process. Change should be guided within the scope, boundary, and the environment of our system of problems, and addresses all interactions and interdependencies of the corporate components. All that requires knowledge, expertise, and teamwork with multidisciplinary approach. On any level, change need to be engineered. Now systems engineers, systems developers, and system analysts are needed to work together with System-oriented managers to guarantee the correct and successful deployment of the change. They use system methods, which utilize number of tools and techniques, for development. Systems thinking requires more than development methods, or step-by-step linear approach, it requires methodologies which far more general and systemic than the systematic application of change. Each methodology space covers the activities to be carried out within the development phases (known as system development life cycle), starting from strategic planning to post-implementation phase. Throughout the years many methods have been developed, and now more than thousand exists (Bubenko, 1986). Review of some of these methods can be found in (Samir, 2002, in Arabic), and more management of change methodologies can be found in (Holmn, and Devan, 1999). In this site we present information about various methodologies used for systems development with its useful links. Also, we introduce the Total Unified Methodology (TUM), developed by the author to handle the requirements for problem definition, reengineering, process design with performance and quality measures, and system implementation. It can also integrate all development projects as ISO certification, BPR, and TQM to be carried out under one umbrella of systems development. More about this methodology can be found in Samir (2002).