Book excerpt: Soil classification and terminology are fundamental issues for the clear understanding and communication of the subject. However, while there are many national soil classification systems, these do not directly correlate with each other. This leads to confusion and great difficulty in undertaking comparative scientific research that draws on more than one system and in making sense of international scientific papers using a system that is unfamiliar to the reader. This book aims to clarify this position by describing and comparing different systems and evaluating them in the context of the World Reference Base (WRB) for Soil Resources. The latter was set up to resolve these problems by creating an international 'umbrella' system for soil correlation. All soil scientists should then classify soils using the WRB as well as their national systems. The book is a definitive and essential reference work for all students studying soils as part of life, earth or environmental sciences, as well as professional soil scientists.Published with International Union of Soil Sciences