This chapter provides a tutorial introduction to the logic of closed-loop systems. A series of examples is presented to illustrate the dynamics of closed-loop systems and to contrast the behavior of these systems with expectations suggested by the logic of open-loop causal systems. In particular, the examples show that “feedback” per se is insufficient to guarantee convergence on a target. The chapter explores some of the issues that must be addressed in order to determine whether closed-loop systems will be stable. Parallels to the phenomena of cognition in the wild are highlighted, and the case is made that the logic of closed-loop systems is an essential foundation for understanding the behavior of cognitive systems.