Organotins are widespread contaminants especially of water environments. Their chemically versatile structure makes organotin compounds able to bind to a variety of biomolecules thus widely affecting biological functions. Trisubstituted molecules, namely tributyltin (TBT) and triphenyltin (TPhT), have been widely employed in antifouling paints and are also exploited as plastic stabilizers that unfortunately cause harmful biological effects. Persistent bioaccumulation has resulted in organotins becoming a significant environmental threat. Chapter by chapter, the biological and biochemical effects of organotins are unravelled in this e-book by a careful analysis of the most recent findings with special focus on contaminant action mechanisms at cellular and molecular level. The e-book provides an intriguing insight into the molecular mechanisms involved in organotin toxicology thus serving as a useful reference to biochemists, biologists, ecotoxicologists and life science students.