The invasion of the land by plants (‘terrestrialization’) was one of the most significant evolutionary events in the history of life on Earth, and correlates in time with periods of major palaeoenvironmental perturbations. The development of a vegetation cover on the previously barren land surfaces impacted on the global biogeochemical cycles and the geological processes of erosion and sediment transport. The terrestrialization of plants preceded the rise of major new groups of animals, such as insects and tetrapods, the latter numbering some 24 000 living species, including ourselves. Early land-plant evolution also correlates with the most spectacular decline of atmospheric CO₂ concentration of Phanerozoic times and with the onset of a protracted period of glacial conditions on Earth. This book includes a selection of papers covering different aspects of the terrestrialization, from palaeobotany to vertebrate palaeontology and geochemistry, promoting a multidisciplinary approach to the understanding of the co-evolution of life and its environments during Early to Mid-Palaeozoic times.