Advances in Agronomy continues to be recognized as a leading reference and a first-rate source of the latest and best research in agronomy. As always, the topics covered are varied and exemplary of the panoply of subject matter dealt with by this long-running serial.Volume 68 contains five outstanding and contemporary reviews on topics that deal with soil chemistry, plant physiology, plant nutrition, and soil and crop management. Chapter 1 by Morris Schnitzer summarizes the past and present knowledge of the chemistry of soil organic matter. Chapter 2, written by H.S. Saini and M.E. Westgate, is a comprehensive exposition on the reproductive development in grain crops during drought. G. Xu, H. Magen, J. Tarchitzky, and U. Kafkafi present advances in chloride management in Chapter 3. Chapter 4 is a review in our continuing series on the 12 soil orders. S.W. Buol and H. Eswaran provide an enlightening review on Oxisols. K. Kumar and K.M. Goh discuss aspects of crop residues in the fifth and final chapter of this important and well-written book.