Contributing author Trefor Evans, PhD, has worked in the hair care industry for more 20 years, with the majority of his time spent as a manager in the product development labs of Helene Curtis and Unilever. He also served for fi ve years as director of measurement services at TRIPrinceton before establishing his own consultancy, TA Evans LLC.
Evans holds a doctorate in physical-analytical chemistry and specializes in measurement science. He holds seven patents related to hair care, and has published numerous articles in trade magazines and scientific literature. His work has been awarded twice by the Society of Cosmetic Chemists, and he is a co-author and co-editor of the book Practical Modern Hair Science, published by Allured Business Media.