The dynamics of cyclic feedback systems are described. The emphasis is both in showing the diversity of possible dynamics in these sytems and in showing that there is a underlying dynamic structure possessed by all these systems. In particular. for the special class of monotone cyclic feedback systems. the dynamics is fairly simple; the recurrent sets can only consist of fixed points or periodic orbits and in many cases can be shown to be Morse-Smale. This is contrasted with the general cyclic

more »

... eedback systems for which chaotic dynamics can occur. The general properties which large subclasses of these systems have in common include periodic orbits and a semi-conjugacy onto a simple. but non-trivial. model dynamical system. To describe all systems simultaneously. a purely topological description of the invariant sets is introduced.