This fully updated and expanded new edition offers a complete overview of hornworts, liverworts, and mosses—diverse groups of land plants that occupy many habitats throughout the world. Revised classifications incorporate contributions from the most recent phylogenetic studies. Six new chapters have also been added, focusing on Physcomitrella to plant genomic research, population ecology of bryophytes, mechanisms of drought tolerance, a phylogenomic perspective on land plant evolution, and problems and progress of bryophyte speciation and conservation. Rich in primary source references and written by leaders in the field, this comprehensive text is suitable for advanced students and researchers.