W. (Bill) Wei is a senior conservation scientist in the Cultural Heritage Agency of the Netherlands, Amsterdam. He has a BSE in mechanical engineering (Princeton University, 1977) and a PhD in materials science (University of Illinois at Urbana-Champaign, 1983). Before working in cultural heritage, he spent almost 20 years in industrial materials research and development in the areas of fracture mechanics, fatigue, and corrosion. Dr. Wei has since been conducting research and consulting on the effects of vibrations and mechanical stresses on the condition of fragile works of art for more than 20 years. He also conducts research on perception related to conservation treatments and object appearance, risks for objects due to mechanical loads, and conservation ethics.