This is an individual chapter of Theory of Constraints Handbook. The purposes of this chapter are to: âEUR cents Briefly explain the history of planning and control systems for single and multi-projects in the project management field, explaining their benefits over the previous system and their restrictions. Recognize each limitation to traditional project management found in the literature (who and when and recommendation to get over limitation, if offered). For each limitation, discuss how crucial chain overcomes that limitation. âEUR cents Survey and categorize the important theory of restrictions planning and control literature in project management, determining its contributions to the field and its restrictions. âEUR cents Identify the need for future research study in crucial chain project management.