K. LAL GAURI, PhD, a Professor Emeritus at the University of Louisville, obtained a PhD in geology at the University of Bonn, Germany. After postdoctoral research at California Institute of Technology, he joined the University of Louisville in 1966, retiring in 1998. A permanent member of the committee of the International Congress on Deterioration and Preservation of Stone Objects, Dr. Gauri was president of its Fourth Congress, held in Louisville in 1982. He was the president of Sigma-Xi's Louisville chapter in 1974 and 1994. JAYANTA K. BANDYOPADHYAY, PhD, received his PhD in chemical engineering from Jadavpur University, India. As a research fellow at National Chemical Laboratory, he came to join Dr. Gauri as a research associate in 1993. He is presently a Research Engineer at United Catalysts, USA. He is a life member of the Indian Institute of Chemical Engineers and a member of the American Institute of Chemical Engineers and the American Chemical Society. Dr. Bandyopadhyay has contributed to the modeling techniques described in this book, in addition to writing the Web component of the book.