This book is about reviewing and exploring the opportunities for introducing increased functionality into coating systems. The intention is to not only provide an account of recent developments, such as other books of this genre, but to also review, in detail, the nature of the problems that we are trying to address in advancing the materials science of coating systems. To this end we examine the fundamentals of corrosion science, the materials science of coatings, and developments in characterisation methods that all help to give an overview of the field. Importantly, we also look at the needs of industry with respect to developments in the coatings field.