Howard Armstrong has been researching micropalaeontology for twenty years and has published extensively on applied micropalaeontology, numerical biostratigraphy, conodont palaeobiology and dispersal biogeography. His research currently focuses on environmental and biological patterns and processes associated with Palaeozoic glaciations. He is Senior Lecturer in Micropalaeontology at the University of Durham. Martin Brasier began research as a marine biologist aboard HMS Fox in 1970, mapping the microbial ecology of Caribbean reefs and algal mats. The author is well known for the first edition of Microfossils and for his work on early biosphere evolution, integrating microfossils, biogeochemistry and chemostratigraphy from the earliest signs of life in the Archaean through to the Cambrian explosion of multicellular forms. He maintains a special interest in the metabolism and evolution of bacterial and protist fossil groups, and has worked with NASA on the protocols for recognition of the earliest life on Earth and beyond. He is currently Professor of Palaeobiology at the University of Oxford.