A comprehensive account of taxonomy; including historical overviews; the first cladistic analyses of bacteria based on classical evidence; the most comprehensive cladistic analyses of eukaryotes based on classical evidence, cladograms, tables and lists; descriptions of the various groups; profiles of taxonomists; and coverage of classifications for lower groups, evolution, and fossils; with edits and a chapter on ecology and biogeography and one on geological time added for this 2nd edition.