This paper presents a unified framework for pull production control mechanisms in multi-stage manufacturing systems. A pull production control mechanism in a multi-stage manufacturing system is a mechanism that coordinates the release of parts into each stage of the system with the arrival of customer demands for final products. Four basic pull production control mechanisms are presented: Base Stock, Kanban, Generalized Kanban, and Extended Kanban. It is argued that on top of any of these basic coordination mechanisms, a local mechanism to control the work-in-process in each stage may be superimposed. Several cases of basic stage coordination mechanisms with stage work-in-process control are presented, and several production control systems that have appeared in the literature are shown to be equivalent to some of these cases.