Interest in bryophytes has undergone a resurgence in the last decade. This renewed focus on the mosses, liverworts, and hornworts has converged from diverse quarters within the scientific community. With recent advances in DNA sequencing technology and analytical approaches to phylogeny reconstruction, systematists have made unprecedented progress toward reconstructing the “tree of life.” One of the truly monumental events in the history of life was the origin of land plants, or Embryophytes. The bryophytes have long been considered a pivotal group positioned at or near the base of the embryophytes and a great deal of molecular work has recently been aimed at resolving relationships among the disparate groups of bryophytes, and their relationships to the tracheophyte clade (see chapter 4). At the same time, the utility of bryophytes, especially mosses, for analyses of plant function and development has been increasingly appreciated and capitalized upon (see chapter 7). Haploidy and structural simplicity among land plants gives the mosses “added value” for research in functional genomics and several species are presently being utilized as model systems (see chapter 5). The ecological importance of bryophytes has long been appreciated, but recent concerns about the implications of global climate change has focussed renewed attention on some bryophyte-dominated ecosystems, especially boreal peatlands (see chapters 10 and 11).

The idea for this volume came about from two divergent directions. Schofield's recent textbook of bryology is no longer in print, and students in bryology classes have few other succinct options.