About the Author: Norman S. Allen, PhD, DSc, is Professor and Chair of Applied Chemistry at Manchester Metropolitan University. Professor Allen has published some 600 papers, articles, books, and book chapters. He is the founder and a member of the editorial board of the journal Dyes and Pigments. He is also founder of the journal Polymer Photochemistry and is on the editorial board of Journal of Vinyl and Additive Technology and Polymer Degradation and Stability. Professor Allen is also Editor in Chief of the Open Materials Science Journal. From 1978-2007 he was the specialist reporter for the section on "Polymer Photochemistry" in the Royal Society of Chemistry's Photochemistry series.