Section I Selected Aquatic Plant Organisms.- Dasycladaceae: A Family of Giant unicellular Algae Ideal for Research.- Acetabularia: A Giant Unicellular Organism for Studying Polarity.- Model Algal System to Study Plant Development.- Section II Selected Aquatic Animal Organisms.- Experimental Analysis of Developmental Processes in Marine Hydroids.- Reproduction and Development in Ctenophores.- Descriptive and Experimental Embryology of the Turbellaria: Present Knowledge, Open Questions and Future Trends.- Growth, Degrowth and Regeneration as Developmental Phenomena in Adult Freshwater Planarians.- Genealogy, Geometry and Genes: Experimental Embryology of Caenorhabditis elegans.- Gap Junctional Communication and Cell Cycle Duration in the Early Molluscan Embryo.- In vitro Preparation of the Early Squid Blastoderm.- On the Establishment of Polarity in Polychaete Eggs.- Experimental Embryology in Leeches: Cellular and Molecular Approaches.- Practical Approaches to the Study of Nervous System Development in Hirudinid Leeches.- Starfish Oocytes and Sea Urchin Eggs as Models to Study the Intracellular Mechanisms Controlling the Cell Division Cycle.- Morphogenesis in the Sea Urchin Embryo: Mechanism of Gastrulation.- Fertilization in Aquatic Animals.- Patterns of Gene Expression during Ascidian Development.- Some Contributions of Research on Early Teleost Embryogenesis to General Problems of Development.- Gastrulation in the Zebrafish Brachydanio rerio (Teleostei) as seen in the Scanning Electron Microscope.- Section III Historical and Conceptual Aspects of "Causal Embryology".- L'Epigenese et la Preformation a l'Epoque de l'Embryologie Causale.- Section IV Contributions of General Value to Embryological Research.- The Role of Retinoic Acid in Vertebrate Limb Morphogenesis.- Physiological Approach to the Early Embryogenesis.- Environmental Pollution and Embryonic Development: Relevance of Standardized Toxicological Tests.- Participants Photo.- Author Index.

The NATO Advanced Study Institute on "Experimental Embryology in Aquatic Plant and Animal Organisms" was attended by more than 70 participants, including 15 invited main lecturers from 18 different countries. In accordance with the main purpose of the meeting, senior scientists, postdoctoral investigators and graduate students working in areas of descriptive and experimental embryology, classical, molecular and developmental biology, physiology and biochemistry etc. , were brought together for two weeks as a community with a strong common interest in "development"; that is, the multiple phenomena and mechanisms, in molecular, cellular, genetic and organismic terms, observed in the development of aquatic organisms. Initial concern that the great variety of biological models as well as of research subjects would harm the scientific quality and coherency of the course was unnecessary. It was exactly this breadth which made the Institute worthwhile for each of the participants. Since many of the "students" were younger scientists starting a career, it was the main goal of the course to offer a concise overview of selected system models of primarily aquatic organisms and to present and discuss research carried out in the past and in progress. Thus, each main speaker gave two in-depth lectures: one in which he presented an overview of "his" model and another dealing with current investigations.