Fossils are essential to the reconstruction of the evolution of life and episodes in Earth history. Knowledge of biomineralization – the processes associated with the formation of mineralized biological structures – is essential to properly evaluate data derived from fossils. This book emphasizes skeletal formation and fossilization in a geologic framework in order to understand evolution, relationships between fossil groups, and the use of biomineral materials as geochemical proxies for understanding ancient oceans and climates. The focus is on shells and skeletons of calcareous organisms, and the book explores the fine structures and mode of growth of the characteristic crystalline units, taking advantage of most recent physical methodological advances. The book is richly illustrated and will be of great interest to advanced students and researchers in paleontology, Earth history, evolution, sedimentology, geochemistry, and materials science.