This volume discusses in particular the suggested relationship of microsaurs with reptiles and the determination of the ancestry of the various groups of living amphibians. Twenty-five general of microsaurs are recognized in this work. Contents: History of the Microsaur Concept, Definition of Micrausaurs, Methods of Study, Taxonomy, Systematic Description, Comparative Anatomy, Relationships of Microsaurs, Geological and Geographical Distribution and Biology of Microsaurs, Summary, and References Cites. Illustrations.