The significance of organometallic chemistry has constantly increased during the second half of this century. The Gmelin Institute recognizes this fact in publishing an entire series on organometallic compounds. This series has now started with the description of the organogermanium compounds. The present second volume in the organogermanium series continues the description of Ge(CH3)3R compounds, beginning with R=alkenyl and concluding with R=heterocycle. The remaining part of the volume covers completely the type Ge(C2H5)3R, which is the most voluminous of the GeR3R compounds. The volume concludes with an empirical formula index.