This volume summarizes our currentunderstanding of biological soil crusts (biocrusts), which are omnipresent indryland regions. Since they cover the soil surface, they influence, or evencontrol, all surface exchange processes. Being one of the oldest terrestrialcommunities, biocrusts comprise a high diversity of cyanobacteria, algae,lichens and bryophytes together with uncounted bacteria, and fungi. The authorsshow that biocrusts are an integral part of dryland ecosystems, stabilizingsoils, influencing plant germination and growth, and playing a key role incarbon, nitrogen and water cycling. Initial attempts have been made to usebiocrusts as models in ecological theory. On the other hand, biocrusts are endangeredby local disruptions and global change, highlighting the need for enhancedrecovery methods. This book offers a comprehensive overview of the fascinatingfield of biocrust research, making it indispensable not only for scientists inthis area, but also for land managers, policy makers, and anyone interested inthe environment.