This is an individual chapter of Theory of Constraints Handbook. This chapter examines the application of the Theory of Constraints (TOC) to production environments. We begin by establishing the Drum-Buffer-Rope (DBR) system which arises through the application of the 5 focusing steps of TOC to production environments. The standard elements of DBR exist in addition to a detailed example which shows the entire procedure. We then review the Buffer Management (BM) method which is a crucial element in using DBR for handling operations. BM supplies the control system to DBR along with valuable input for driving an enhancement procedure. We then present the TOC method for the category of complex production operations. Based upon the flow qualities of the production procedure this approach leads to four significant types of production operations âEUR" V, A, T and I. We close the chapter with a discussion of the category requirements, the key characteristics and operational problems of each kind of plant and the standards for the application of DBR in each production type.