This volume provides a critical description of the methods used to probe the energetics of organic free radicals, including methods in: gas-phase and in solution, appearance energy measurements, photoacoustic calorimetry, electrochemical techniques and theoretical calculations. It also offers a critical review of the currently available data. This text is primarily directed at researchers and graduate/advanced undergraduate students in organic chemistry and biochemistry, but it is also intended to be of use as a reference source for food scientists, medicinal chemists, catalysis and surface scientists, fuel and combustion chemists, and chemical engineers.