This volume is a summary of the current state of knowledge on vitamin C (ascorbic acid), the major watersoluble antioxidant vitamin, which was discovered by Albert Szent-Györgyi (Nobel Prize in 1937), resulting from research work in basic science, epidemiology and clinical medicine. Fundamental molecular, biological and physiological properties of ascorbic acid are presented, and the current knowledge on the role of vitamin C in major diseases such as cancer, cardiovascular and respiratory diseases is critically evaluated. The aim is to contribute to a better understanding of the potential beneficial use of the compound in disease prevention or treatment. The topics are presented by renowned international experts.