Book excerpt: This book illustrates the importance and significance of oxidative stress in the pathophysiology of various human diseases. The book initially introduces the phenomenon of oxidative stress, basic chemical characteristics of the species involved and summarizes the cellular oxidant and anti-oxidant system and the cellular effects and metabolism of the oxidative stress. In addition, it reviews the current understanding of the potential impact of oxidative stress on telomere shortening, aging, and age-related diseases. It also examines the role of oxidative stress in chronic diseases, including cancer, diabetes, cardiovascular diseases, and neurodegenerative disorders. Further, the book presents novel technologies for the detection of oxidative stress biomarkers using nanostructure biosensors, as well as in vitro and in vivo models to monitor oxidative stress. Lastly, the book addresses the drug delivery carriers that can help in combating oxidative stress.