Since 1965 Dr. Ruetzler been a research biologist and curator of lower invertebrates in the National Museum of Natural History. In 1985 Klaus was appointed director of the newly conceived Caribbean Coral Reef Ecosystems Program (CCRE) at NMNH. Ruetzler also serves a member of the editorial board of the international journal Marine Ecology (since 1979). Previous positions included Assistant Research Curator at the Museum of Comparative Zoology, Harvard University, 1963; and Research Associate, Institute of Zoology, University of Vienna, Austria, 1964–1965. Dr. Ruetzler’s holds a Ph.D. from the University of Vienna, Austria (1963) where he worked on sponges of Mediterranean submarine caves. He then continued pre-employment field research on sponge biology and ecology Croatia, Italy, Bahamas, Puerto Rico, Malaysia, Thailand, Indonesia and Madagascar. His major professional interests are biology and ecology of sponges (Porifera); symbiosis and disease in lower invertebrates; bioerosion; and biodiversity and ecology of tropical coastal communities.