This series explores the five accepted kingdoms that make up the living world - animals, plants, fungi, protista, and bacteria - and one kingdom currently proposed by scientists: other single-celled microorganisms called Archaea. Each book deals with a particular kingdom and the topic of taxonomy (classification) of its organisms, and explains how the organisms are classified into the smaller groups of phylum, class, order, family, genus, and species. Also covered are the ways in which the different organisms are used by people and how they interact with organisms of other kingdoms. The differences between the different kingdoms are covered, too. Case studies involve recent scientific research and applications.