Marburg and Ebola virus, the two species within the family Filoviridae, are among the most pathogenic agents causing fulminant hemorrhagic fever in humans and nonhuman primates. The chronology of filovirus epidemics and epizootics proves that these viruses are prototypes of emerging/re-emerging pathogens. Since the discovery of Marburg virus in 1967 until the recent Ebola virus outbreaks in Central and West Africa filoviruses have not only raised the interest of scientists, but have also been a matter of high public concern. With the advent of recombinant DNA technology our knowledge on the genome structure and the replication strategies of these agents has significantly increased. This volumes gives an overview on many aspects of filovirus research and summarizes recent advances in the field. The topics addressed include the molecular biology of filoviruses, pathogenesis, epidemiology, immune response, as well as clinical aspects and diagnostic measures.