Polymers are ubiquitous in nature, owing to their use as both structural and active components in dynamic, living systems. From a synthetic point of view man has utilized the excellent structural properties of polymers (light weight/high strength) for some decades now. However, the integration of active functional polymers into engineered systems and structures is a more recent endeavour with numerous challenges still to be overcome. Conducting electroactive polymers such as polypyrroles, polythiophenes and polyanilines are a fascinating group of functional polymers. They are electronic conductors and in addition they response to chemical or electrical stimuli in a number of ways. They are truly electrofunctional polymers. This unique combination of properties has led to the use of conducting polymers for electronic components, chemical sensors and biosensors, membranes for solution or gas separations, electromechanical actuators, electro-optical devices, biomaterials capable of controlled release of drugs or stimulation of biological processes, and for corrosion protection.