Neutral reactive intermediates -- radicals, carbenes, nitrenes, and aryenes -- occupy a fascinating place in the history of organic chemistry. First regarded as mere curiosities, neutral reactive intermediates ultimately came under the intense scrutiny of physical organic chemists from a mechanistic point-of-view. This concise text concentrates on how these electron-deficient species now play a key role in synthetic chemistry research. Important reactions are clearly and simply laid out with carefully chosen examples that illustrate their use in organic synthesis. Each chapter includes problems as well as suggestions for further reading. Undergraduates will find Reactive Intermediates an invaluable summary of this important topic in organic chemistry--one that fills a gap created by the superficial treatment accorded these valuable compounds in most chemistry textbooks.