Editor in Chief Dr. Pan Ming Huang died on September 13, 2009, aer a short illness. He was a towering leader in the eld of soil science, and soil chemistry in particular, having served the profession for over 44 years formerly as professor of soil science at the University of Saskatchewan, Saskatoon, Saskatchewan, Canada. He was a dedicated teacher and author of over 300 journal articles published in the most prestigious journals. In the midst of the revision of the Handbook of Soil Sciences, having developed and approved the outline, set the standards for the contributions, and solicited the cooperation of all the associate editors, he unexpectedly fell ill. One of his strengths was his ability to involve, organize, and inspire colleagues to cooperate in pursuing scientic endeavors as was evidenced by his initial inputs into this work. Unfortunately, he passed away before being able to see any of the fruits of his labors, the completed manuscripts. Dr. Huang is survived by his wife, Yun Yin, who was gracious in the handover of all the materials required for us to complete the handbook in a timely manner. We dedicate this book to Dr. Huang as a lasting memorial to his many contributions to soil science.