The use of allenes, hydrocarbons in which one atom of carbon is connected by double bonds with two other atoms of carbon, has over the past 20 years become more and more popular in organic chemistry, even being used in fields such as metal-catalyzed reactions where their use was previously difficult due do selectivity problems. This monograph, edited by Krause (Organic Chemistry II, U. of Dortmund, Germany) and Hashmi (Institute of Organic Chemistry, U. of Stuttgart, Germany), reviews the research on allenes over the past couple decades, taking the literature up to 2004 into account. They have divided the two-volume text into sections dealing with synthesis of allenes, covering isomerization reactions, metal-mediated synthesis, transition metal-catalyzed synthesis, and enantoselective synthesis; special classes of allenes, including allenic hydrocarbons, cyclic allenes up to seven-membered rings, acceptor- and donor-substituted allenes, and allenylmetal compounds; reactions of allenes, dealing with ionic additions, free radical addition, cycloadditions, cyclization, transition metal-catalyzed cross-couplings and cycloisomerizations, and oxidation; and, finally, applications such as allenic natural products and pharmaceuticals, allenes in natural product synthesis, and enyne-allenes.