structures and/or biological activities, including marine-derived prostaglandins, palytoxin, ciguatoxin, brevetoxin, okadaic acid, tetrodotoxin, saxitoxin, calyculins, and kainic acid. Manoalide is also being sold commercially as a biochemical probe.

In this chapter, we hope to show that marine natural products represent a promising source of potential therapeutic agents, to review some of the strategies and approaches by academic and industrial labs that have led to and are leading to the discovery of marine natural products with therapeutic potential, to highlight the sources of biologically active marine natural products and collection techniques of their respective source organisms, to review the history and status of selected marine-derived compounds that are at various points along the discovery and development path, and to present and discuss some of the unique difficulties in the therapeuticthese structures represent new classes unknown previously from nature or synthesis. Analysis of these reviews indicates that a substantial amount of research has been conducted by chemists in Europe, especially Italy, and in Australia, New Zealand, Israel, Japan, and North America. The greatest number of marine-derived compounds have been isolated from shallow water organisms and their structures published by North American and Japanese researchers, who are located at academic institutions. To our knowledge, a greater number of academic and industrial research groups have become involved in the past several years in the search for biologically active and novel compounds from marine-derived microorganisms, and we expect that this increased effort will be reflected in both the scientific and patent literature in the next several years. Collection sites for the