Biometals can be seen in human bodies. It is classified as a trace element, one that human beings require in very small amounts. In this book, transporter and transporter receptor of important biometals in human beings are discussed, as well as important toxic metals, such as Cadmium (Cd) in occupational and environmental toxicology. Present knowledge on interactions between toxic metal cadmium and essential metals Zn, Cu and Mg are displayed. The authors also provide a detailed view of the current understanding of important features concerning the role of copper in plant physiology and metabolism, with recent findings on copper chaperons, Cu transporters and Cu trafficking. The applications, properties and molecular structures of silver and nickel are also discussed in detail. Moreover, the progress to date on the chemistry and biochemistry of pentavalent antimony are summarized. The most recent works being done to improve antimonial chemotherapy are also presented. Other chapters discuss the Fur (ferric uptake regulator) proteins, a superfamily of prokaryotic transcription factors that operate at the primary steps in the hierarchy of stress responses. The current knowledge on the complex regulation of Fur proteins in cyanobacteria are also summarized. Additional chapters review various quantitation methods for phytochelatins, analyze the complete complement of metal transporters from various Helicobacter species and discuss the preparation of novel pharmaceuticals to fight infections causing more than 20% of overall number of lethal outcomes.