Information related to oxidative stress and diseases has been examined in this book. The formulation of hypothesis of oxidative stress in the 1980s aroused the interest of biomedical and biological sciences which exists in the present day scenario as well. The contributions in this book educate the readers on the role of reactive oxygen species in distinct pathologies in animals as well as humans. The book is designed in such a way that it covers all the particular groups of pathologies like cancer, hormonal, neuronal, and systemic ones. It also elucidates the potential of antioxidants to safeguard organisms against harmful effects of reactive species. This book is a useful source of information for readers including researchers and students.