The moss Physcomitrella patens has been developed as a model organism during the last two decades. Analyses of its transcriptome and genome have revealed differences and commonalities with the genetic systems of seed plants. Comparisons with land plants and algae allowed the inference of evolutionary incidents that occurred with the transition of plant life from water to land. The established molecular tool kit and the available genome sequence together enable future research of plant evolution and development. In this chapter, we elaborate on P. patens biology and evolution, give an overview of the analyses that have been carried out in the last decade, and envision future prospects.