This book illustrates the key role played by taxonomy in the conservation and sustainable utilisation of plant biodiversity. It is a tribute to the work of Professor Vernon Heywood who has done so much to highlight the importance of sound scholarship, training and collaboration for plant conservation. Divided into four parts, the book opens with an overview of the place of taxonomy in science and in implementing the Convention on Biological Diversity. Part 2 outlines the theoretical basis of taxonomy, how it is done and how it contributes to measuring diversity. The third part explains how taxonomy is used to establish conservation priorities and actions and the concluding part illustrates taxonomy in the practice and measurement of effective conservation action. With contributions from taxonomists and also the users of taxonomy, the volume will provide a balanced treatment, suitable for advanced students, researchers and conservation professionals.