In this Volume, containing 24 chapters devoted to carbon attached by single bonds to two heteroatoms, the reader will find several chapters reviewing the synthesis of familiar functional groups, notably acetals, dithioacetals, aminals and the various mixed species. The derivatives with tetracoordinated (saturated) carbon are described in Part I and those, eg. ketene acetals, of tricoordinated carbon in Part II. However, the treatment is comprehensive and the authors have uncovered much fascinating chemistry concerning less familiar groups, including some like geminal halohydrins, halo amines and diols that are often unstable. Again, a surprisingly large number of compounds having two metals attached to the same carbon have been located in the literature, and the abundance of phosphorus derivatives, eg. those with geminal nitrogen functions, reflects their importance as biologically active species and as intermediates in synthesis. Part III consists of a single, short chapter describing dicoordinate carbon (carbenes) and examples of carbon cations, anions and radicals. Here the treatment is deliberately selective since throughout the work as a whole emphasis is placed on the synthesis of isolable species rather than the transient intermediates of organic reactions.