The significant increase in applications of Barbier and Barbier-type reactions in (in-) organic synthesis over the past twenty-five years, combined with repeated stimulation on the part of Springer-Verlag (Dr. R. Stumpe) were strong in­ centives for me to write this book. My earliest activities in this field include a modest and first-ever review article (in cooperation with Dr. F. A. Hartog who at that time (1977) did his doctoral research on the Barbier reaction). References to this review article, as mentioned in the Science Citation Index till recently are a good indication for a continued interest in this simple synthetic procedure. The subtitle of this monograph, Related One-Step Processes, may require the following clarification. A synthesis with the aid of an organometallic compound is usually carried out in two steps: 1) the organometallic reagent is prepared from an organo halide and a metal in a solvent, 2) a chosen substrate is added to this reagent. In a Barbier reaction these two steps are combined: a mixture of the organo halide and the substrate is added to a suspension of the metal-in an appropriate solvent.