Neutral reactive intermediates - radicals, carbenes, nitrenes, and arynes - have an interesting place within the history of organic chemistry. Once regarded as curiosities, then intensively studied from the mechanistic point of view by physical organic chemists, they now play a key role in synthetic chemistry. This concise text concentrates on the last aspect of reactive intermediate chemistry; the important reactions of these electron-deficient species are laid out clearly and simply, with carefully chosen examples illustrating their use in organic synthesis. Each chapter includes a few problems as well as suggestions for further reading, and provides undergraduates with an invaluable summary of this important topic in organic chemistry.