As one of the most abundant minerals, calcium carbonate (CaCO3) has great significance in both geological and biological systems. Of the six calcium carbonate polymorphs, calcite is the most stable one thermodynamically, which has attracted much attention due to its considerable industrial importance and abundant diversity as a biomineral. This book presents topical research in the study of the formation, properties and applications of calcite, including CaCO3 crystallisation in the presence of biomacromolecules; the archaeological significance of calcite; surface properties of calcite in aqueous suspensions; calcite growth in a simulated cooling water environment and calcite in the skeletons of annelids.