Used by humans since ancient times, evergreen oak forests still cover extensive mountain areas of the Mediterranean Basin. These broadleaved evergreen forests occupy a transitional zone between the cool-temperate deciduous forest biome and the drier Mediterranean pine forests and shrublands. Slow growing and casting a deep shade, the sclerophyllous holm oak ("Quercus ilex") absolutely dominates the closed canopy of many Mediterranean evergreen oak forests. This is a synthesis of 20 years of research on the structure, function, and dynamics of holm oak forests in two intensively studied experimental areas in Spain. By combining observational measurements at the leaf, tree, plot, and catchment scales with field experiments and modelling, the authors explore how these forests cope with strong water limitation and repeated disturbances.