Breakdown is fascinating to the scientist and frustrating to the engineer! As well as advancing the scientific and engineering understanding of electrical degradation and breakdown in polymers, this book forms a comprehensive and international review of the state-of-the-art. Topics include: water and electrical treeing; charge transport; 'classical' and filamentary thermal, electromechanical, electronic and partial discharge breakdown models; the stochastic nature of breakdown and statistical characterisation techniques; and engineering considerations for breakdown testing and degradation assessment. The treatment presumes little prior knowledge but develops into an advanced understanding of new concepts such as the fractal-like nature of trees. Although the book is primarily aimed at scientists and engineers practising in the field, a broad introductory section has been included to cater for a wide audience including those new to the subject area. This comprises a description of the nature of the polymers, basic solid-state physics and an introduction to degradation and breakdown.