“Die gegenseitige Beeinflussung der höherer Pflanzen – Allelopathie” by Gerhard Grümmer appeared in 1955. It was a remarkable and unique summary of a science, that had received little attention, but which was to captivate the attention of plant ecologists decades later. While Hans Molisch was credited for coining “allelopathy” (in German) in 1937, his monograph dealt primarily with the effects of ethylene. It was Gerhard Grümmer, a young academic at Ernst-Moritz-Arndt University, Greifswald, who marshalled the existing world literature on the chemical interactions of plants into the world's first coherent textbook on allelopathy. Grümmer, however, worked in East Germany, at a time when the “iron curtain” was descending, and his book on allelopathy remained little known outside Germany. In 1957, the book was translated into Russian, which helped advance subsequent allelopathic studies in the U.S.S.R. In the English-speaking world, the first comprehensive mono-graph on allelopathy is considered to be “Allelopathy” by E.L. Rice, published in 1974, and revised in 1984. While Molisch's heralded book has been both reprinted, and translated into English, Grümmer's meritorious volume has been sadly overlooked, and to this day still provides important insights into many allelopathic problems, in particular root excretions, pollen allelopathy, and chemical interactions in mistletoes. For these reasons, an English trans-lation of “Die gegenseitige Beeinflussung der höherer Pflanzen – Allelopathie” is long overdue, and it is hoped that its publication will assist ecologists in their research and consolidate Grümmer's position as a founding figure in the development of allelopathy as a science.