It is widely accepted that new drugs, especially anticancer drugs and antibiotics, are urgently required. Despite the recent de-emphasis on natural product research by the pharmaceutical industry, no other drug discovery platform has proved to be as effective in yielding unique chemical structures with either direct application in the treatment of disease or the capacity to serve as chemical scaffolds from which molecules with enhanced efcacy can be derived. There is little doubt that myriad structural motifs remain undiscovered from natural sources and that these molecules will be an important source of new medicines in the future (Jensen et al. 2005). Due to a recent deceleration in natural product research in terrestrial habitats, there is increasing interest in the exploration of marine microorganisms for novel metabolites such as anticancer and antimicrobial compounds. In exploring new sources of bioactive natural products, the marine environment warrants particular attention in view of its remarkable diversity of microorganisms and metabolic products. The oceans are highly complex environments and house a diverse assemblage of microorganisms that occur in environments with extreme variations in pressure, salinity, and temperature. The oceans cover around 70% of the Earth’s surface and present themselves as an unexplored area of opportunity. Marine microorganisms encompass a complex and diverse assemblage of microscopic life forms, of which it is estimated that only 1% has been cultured or identied to date (Bernan, Greenstein, and Carter 2004). It is estimated that marine environments, including the subsurface, harbor approximately 3.67 × 1030 microorganisms (Whitman, Coleman, and Wiebe 1998) that represent an extraordinary and dynamic gene pool of biodiversity. The majority of these microbes have never been cultured, identied, or classied, and their enormous chemical richness remains untapped (DeLong 1997). However, in the past two decades this situation has changed as a result of the rapid progress achieved in related elds. The search for bioactive compounds is presently reaching a new dimension with such diverse approaches as genomics, proteomics, bioinformatics, combinatorial biosynthesis, combinatorial chemistry, targeted drug development, directed evolution of key enzymes, phage-display libraries, automation, and high-throughput screening (Wagner-Dobler et al. 2002).