Electrochemistry no longer is a specialist discipline, but has become a technique of major importance for most inorganic and organometallic chemists. Similarly, electron-transfer activation has led to great progress in transition-metal mediated organic and inorganic syntheses. This book provides a unique introduction and overview of the structure and reactions of transition-metal radicals, of transition-metal electrochemistry, and of electron-transfer activation, with emphasis on catalytic processes. Each chapter of this book includes numerous citations of the chemical literature, lots of examples and illustrations and the book is written in an extremely readable style. It will serve as a useful tutorial for a wide spectrum of students, chemists, and chemical engineers involved in organic, inorganic, and organometallic chemistry.