This Special Issue of Biodiversity and Conservation has its inception in a 3-day Conference— ‘‘Biodiversity Crisis on Tropical Islands’’—organized by the Department of Biology, Universiti Brunei Darussalam and held at the University campus from 11th to 13th June 2007 as part of the 20th Anniversary of the founding of this relatively new University on Borneo Island. With generous university funding, the conference organisers were able to invite several distinguished keynote speakers to deliver plenary addresses on biodiversity issues related to islands in the tropics. These and other presentations, plus additional invited keynote contributions, resulted in a series of manuscripts which are more than a record of the Conference proceedings. Biodiversity depletion is considered to be, or should be, of crucial importance in the wider sphere of human affairs and in this context the invitation to contribute papers was further extended to other biodiversity researchers, including several keynote invitees, who, due to other commitments, were unable to participate in the Conference itself. Fortuitously, but fittingly, the Conference and the preparation of this Special Issue also coincided with the 150th anniversary of the publication of Charles Darwin’s ‘Origin of Species’. The very last lines of this book encapsulate the grandeur of the diversity of life on Earth with the oft-quoted words ‘‘... from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved’’. Darwin and his contemporary, Wallace, in the development of their ideas on evolution, drew extensively on the recognition of islands as species ‘foundries’, yet widespread realization of the vulnerability of island life to extinction has come much later as Malthusian projections of human population pressure on biotic resources have become a reality. Islands, often with a high proportion of endemic, in effect ‘limited-edition’, species have accounted for the bulk of the world’s recognized extinctions of species in historical times. Additionally, these recognised loses alone have undoubtedly taken with them, to oblivion, a far greater number of obligately associated organisms (including symbionts, parasites and parasitoids), many of which may not even have been named. Much of the Earth’s terrestrial biodiversity is located at tropical latitudes, in the rainforests, and the