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.