One of the most important of these systems is the frontal cyclone (see Figure). Although they were first identified in the middle of the nineteenth century, it has only been recently that my research has led to the identification of the dynamical process responsible for their development. Research is continuing into this important new bifurcation which we have called the cyclone-scale mode of baroclinic instability. The preferred region for the development of this new instability are the regions of enhanced thermal gradients known as frontal zones. These zones are the result of large-scale atmospheric circulation that acts to concentrate the initially uniform equator-to-pole temperature contrast into a narrow zone. The cyclones that develop via this mechanism draw on the potential energy stored within the front.