This book highlights the role of some metals which induce oxidative stress and imbalances in the neurodegenerative diseases such as Alzheimer disease, Parkinson disease, Amyotrophic Lateral Sclerosis, Huntington Disease, and other dementias. The chemistry and biochemistry of metals induced-oxidative stress, protein damage is first described, followed by the evidence for a pathological role of oxidative stress in these disease states. It is tempting to speculate that free radical oxygen chemistry contributes to pathogenesis in all these conditions, though it is as yet undetermined what types of oxidative changes occur early in the disease, and what types are secondary manifestations of neuronal degeneration. Finally the authors review different metals to describe their specific role in the different pathologies.