Oxidative stress arises when there exists an imbalance between the biological system's inability to detoxify reactive intermediates and thereby repair the damage, and the systemic manifestation of reactive oxygen species. Aging is a physiological state in which there is a progressive decline of organ function along with the incidence of age-related diseases. The oxidative stress theory of aging suggests that free radicals or reactive oxygen species create damage which gives rise to symptoms of aging. It is claimed that the oxidative stress within mitochondria may lead to a progression of events in which damaged mitochondria produces increased number of reactive oxygen species, which leads to further damage. This book covers in detail some existing theories and innovative concepts revolving around oxidative stress and aging. Different approaches, evaluations, methodologies and advanced studies on the role of oxidative stress in aging have been included herein. This book, with its detailed analyses and data, will prove immensely beneficial to professionals and students involved in this area at various levels.