The Theory of Constraints is about applying a mindset of ongoing improvement to your organization. It contains the notion of applying efforts to improve to the areas that will have the most impact and offers some practical techniques for achieving this.
In ‘Agile’ circles there are certain topics that come up frequently, such as Kanban and Scrum, so much so that we often forget that Agile is a mindset rather than a small subset of methodologies.
Henry Ford exemplified the Theory of Constraints and Systems Thinking. His obsession with flow made him the most successful business man of his time.