Metals play a vital role in the metabolism of plants and animals and, increasingly, in medicine. This book provides an introduction to the metals essential to life and ligands of biological importance. It considers the uptake of metals, their transport and ultimately their storage, illustrated in particular with the story of iron in the body. It also considers Na, K and Ca ion channels and biomineralisation and covers the key roles that metals and their complexes play in living systems, for example in respiration and photosynthesis. The last chapter (delivered online) considers metal toxicity and deficiency as well as the role that metals play in medicine, looking at both diagnostics and therapy, and in the forefront of inorganic research.