The Fifth International Biomineralization Symposium was held in May 1986 at The University of Texas at Arlington, Arlington, Texas. The chosen theme was the origin, evolution and modern aspects of biomineralization in plants and animals. Thus, the symposium was designed to bring together experts in ocean and atmospheric chemistry, geochemistry, paleontology, biology, medicine and related fields to share accumulated knowledge and to broaden research horizons. The contents of this volume reflect the diversified interests and views of contributors from these fields. Topics range from contrasting views of the origin of ocean chemistry, the cause or causes for the biomineralization among plants and animals, the evolution of style and structure of biomineralization, and the role of inorganic and organic compounds in biomineraliza tion. It was clear from those gathered in Arlington that the efforts of all researchers in any aspect of biomineralization can be strengthened and extended by greater exposure to the work of others in allied fields. At the time of this printing, several collaborative efforts have grown from interest and contacts developed during the symposium. Rex E. Crick viii ACKNOWLEDGEMENTS The symposium would not have occurred with the financial support of The Organized Research Fund of The University of Texas at Arlington and The Sea Grant Program administered by Texas A & M University. The staff of the Department of Geology of The University of Texas at Arlington were largely responsible for providing a pleasant atmosphere for learning.