This Report provides an update of the two-part review of the literature of marine natural products that was published in Natural Product Reports during 1984. The first part of that review covered the literature published between 1977 and October 1983 concerning metabolites of marine algae and herbivorous marine molluscs. The second part reviewed publications reporting metabolites of marine invertebrates during the period 1977 to July 1984. Both areas are now combined into a single Report that continues the coverage until approximately July 1985. A few papers that were omitted from the previous reviews have been included in this Report. Two comprehensive reviews have appeared during this reporting period, on the subjects 'Chemical and Biological Aspects of Marine Monoterpenes'j and 'Paralytic Shellfish Poisons'.s A 'Symposium-in-Print' that is devoted to the chemistry of marine natural products has provided a showcase for research in this field. The papers cover many topics and are reviewed in the appropriate sections. One of the most satisfying aspects of research into marine natural products is the high level of interest that is exhibited by researchers outside the field. The natural symbiosis between marine biology and marine natural products chemistry is noticeably stronger, and the interest of the pharmaceutical industry in the pharmacology of marine metabolites has grown to gratifying proportions. Marine natural products are often the target of research in synthetic organic chemistry. While there are many interesting studies being directed toward the synthesis of marine metabolites, this review will concentrate on examples of total synthesis rather than partial synthesis.