Book excerpt: The present volume opens the Gmelin series on organogermanium compounds, that is, those compounds containing at least one germanium-to-carbon bond. This whole series is being coordinated by Professor J. Satge of the Universite Paul Sabatier in Toulouse. Germanium is of historical interest because its existence was predicted by Newlands in 1864 and by Mendeleeff in 1871 although it was not isolated until1887 by Winkler. Mendeleeff's predictions of the properties of germanium and its compounds by comparison with what was known of the chemistry of its neighbors, silicon and tin, proved remarkably accurate and included predictions of the existence of organic derivatives GeR and of their properties. 4 Although significant applications are as yet lacking for organogermanium compounds in contrast to organo-silicon, -tin, and -lead compounds there has been considerable interest in the parallel development of its chemistry. Up to 1983 about 1500 publications have appeared on organogermanium chemistry. The material of the present series will be grouped in a similar way as for the organotin series beginning with compounds containing only one germanium atom (mononuclear com pounds) and continuing with binuclear up to polynuclear compounds. Within each group the compounds are arranged by the kind of non-carbon substituents rather than by following the usual Gmelin principle of the last position using the Gmelin system of elements.