The current presence of plant species in a particular area is explained by a series of events and processes of a diverse nature – mainly geological and climatic, but also anthropozoogenic – which have occurred over millions of years at different spatial levels. Sunlight is the energy source for plant photosynthesis and one of the major environmental factors influencing the growth and distribution of plant species. Most ferns live in moist and shady environments; however, some are able to recruit energy under high-irradiance conditions. Ferns are much utilized by people, namely for use as ornamental plants, as raw material to make handicrafts, in cosmetics, in foods and in popular medicine. This book discusses the biology, cultivation and implications for the environment of ferns, and also examines the Iberian Peninsula’s shrub species.