Many may know lanthanides under the homier name of rare earth elements, but that is less used scientifically because they are, in fact, not at all rare. Highlighting fast-moving research on lanthanides and their interrelations with biosystems, this book emphasizes the recent impact of these metals in biochemical, biological, and medical research, including in magnetic resonance imaging (MRI). The first two chapters outline their abundance and distribution, chemical properties such as oxidation states and ionic radii, and their mobilization through microorganisms like bacteria and fungi. It is written by 38 internationally recognized experts and enriched with nearly 200 illustrations and 1900 references.