The neuroendocrine control of reproduction and development of inver­ tebrates has a long tradition as an important area of research in France. The reader of this volume is certainly familiar with the significant con­ tributions to this field made by such outstanding scientific personalities as J ean-J acques Bounhiol, Jean Panouse, Bernard Possompes, Pierre and Line Joly, Helene Charniaux-Cotton,Maurice Durchon, Manfred Gabe, Guy Echalier, Marie Raabe, and others. It is therefore not surprising that the Centre National de la Recherche Scientifique (CNRS) sponsored, in 1975 and 1983, two major inter­ national meetings devoted to this subject. The organizers of the 1975 meeting, which was held in Lille, decided to concentrate on the bio­ synthesis, metabolism, and mode of action of the invertebrate hor­ mones. To some extent, Professors Durchon and J oly wanted to convey the message that they felt that the period of classical invertebrate endo­ crinology had come to an end and that traditional approaches were be­ ing replaced by biochemical analyses. How right they were is illustrated by the present volume. Today biochemistry, molecular biology, and analytical chemistry are tools of the invertebrate endocrinologist, who now starts his morning work by homogenizing his worm, mollusc, insect . . . and by extracting DNA, steroids, or peptides.