This text is intended for senior or postgraduate courses in systematics, particularly animal taxonomy. Practical suggestions for taxonomic practice are included and explanations of the basic concepts of taxonomy are emphasized as well as the definition of traditional terms used in taxonomy. The treatment of taxonomy is in two parts. Part A is devoted to microtaxonomy and Part B is devoted to macrotaxonomy. There is a new chapter on the methods of numerical taxonomy, and an extensive treatment of the new approaches in taxonomy.