The book includes new data on the ultrastructure of the somatic cortex of each class, molecular phylogenetics, ecology, and on other important aspects of ciliate biology. These new data are used, along with a novel conceptual approach, to rationalize a new system of classification for the phylum, presented in a major chapter on The Ciliate Taxa. The book includes an up-to-date bibliography of approximately 3,000 citations to both the classical and recent literature, and both a Subject Index and a Systematic Index. This unique and timely book will serve as a comprehensive and authoritative reference work for students, teachers, and researchers who have an interest in the protozoa, and particularly the ciliates.