Volume 1 provides a detailed survey of reactions that entail the 1,2-addition of nonstabilized carbanion equivalents of carbonyl, imino and thiocarbonyl functionality. Emphasis has been placed on those reagents that result in highly selective addition reactions. Methods are reported to select, for example, one carbonyl group over another in the same molecule, or to add preferentially a fragment to one (enantiotopic of diastereotopic) face of a carbonyl group. Processes that result from an initial addition to the C=X functional group, for example alkenations and rearrangements, are also covered in this volume.