Free radical research has become fashionable, as reflected in the abundance of symposia and publications dealing with the subject. However, there is a scarcity of textbooks which deal systematically and in a concise and simple fashion with both the fundamental and the clinically relevant aspects of free radicals and antioxidants. This handbook is a step in that direction. In the introduction, the early scientific discoveries and some theoretical concepts which are seldom acknowledged, despite their importance in paving the way to the contemporary accomplishments, are reviewed. This is followed by a critical review of specific issues in the fields of free radicals and antioxidants, and by a final selection of models and methods for radical-related experimental and clinical research.