Dr. Jennifer Mary Marsh gained an MA (Hons) in Chemistry (First Class) and a PhD for work on "Gold Cluster Chemistry" from the University of Oxford, UK. After working as a Post Doctoral Research Assistant at Texas A&M University, USA, she joined Procter & Gamble Ltd, UK, in 1995. She became a Senior Scientist with the company in 1998 and Principal Scientist in 2003, working as leader of oxidant technology development programmes for hair colorants. In 2007 Dr. Marsh became Principal Scientist at Procter & Gamble, US, where she continues to lead both oxidant technology development programmes for hair colorants and the hair structure understanding group. In 2009 she became a Research Fellow at Procter & Gamble, US, and leader of technology development for hair care. From 2009 to 2011 she was Associate Adjunct Professor at the University of Cincinnati. Dr. Marsh is the recipient of various awards, including the Royal Society of Chemistry Teamwork in Innovation Award, 2009, and the most innovative paper award at the SCC cosmetic conference, 2010. She has published more than 30 papers in peer-reviewed scientific journals and has submitted 13 patent applications. John Gray MBBS, MRCGP is Medical Advisor at Procter & Gamble Beauty and Grooming. Antonella Tosti is Professor of Clinical Dermatology at the Miller School of Medicine of the University of Miami, US. She is also well-known in Europe as she was Professor of Dermatology at the University of Bologna for 20 years. Her research involves hair, nail and cosmetic disorders. She is member of many dermatological societies including the ADA, AAD, EADV, WDS and ISD. She is author of more than 600 publications and 20 books, several of them very successfully with Springer.