Metallothioneins: historical development and overview -- Regulation of metallothionein gene expression -- Bacterial metallothioneins -- Metallothioneins in yeast and fungi -- Metallothioneins in plants -- Metallothioneins in diptera -- Earthworm and nematode metallothioneins -- Metallothioneins in aquatic organisms: fish, crustaceans, molluscs, and echinoderms -- Metal detoxification in freshwater animals. Roles of metallothioneins -- Structure and function of vertebrate metallothioneins -- Metallothionein-3, zinc, and copper in the central nervous system -- Metallothionein toxicology: metal ion trafficking and cellular protection -- Metallothionein in inorganic carcinogenesis -- Thioredoxins and glutaredoxins. Functions and metal ion interactions -- Metal ion-binding properties of phytochelatins and related ligands.