David M. Williams is a diatom researcher and Head of Global Biodiversity Group in the Department of Botany, The Natural History Museum, London. He has published over 150 scientific papers, including 6 books. Among his books he is a co-author of the standard text Cladistics: The Theory and Practice of Parsimony Analysis (1992) and co-editor on Models in Phylogeny Reconstruction (1994) and Milestones in Systematics (2004). He is interested in the history and theory of systematics and biogeography and the systmatics of diatoms.-Springer