The Theory of Constraints (TOC) is a philosophy of management and continuous improvement originally developed by Dr. Eliyahu M. Goldratt and introduced in a book called The Goal. The book, a novel, is often used in business classes. The story, which is told in first person narrative, is about a new plant manager who is given ninety days to turn things around and make the plant run successfully or the plant will close. The plant manager finds a mentor who asks questions that guide the manager -- and the reader -- to realize that every complex system has at least one constraint (bottleneck) and it's the constraint that determines the ability of the system to be successful.
This white paper from the Goldratt Institute provides an introduction to the Theory of Constraints and its thinking processes.