The evolution of landscapes is governed by a few simple principles which can be viewed in the context of complexity-theory: landscapes can be regarded as open nonlinear systems in which tectonic processes furnish the input and denudational processes the output (Antagonism Principle). Stationary states in a landscape correspond to self-structured order in a complex system; they exist in a limited range of space and time only, they are selected for some finite duration in a limited region (Selection Principle). Geomorphology has mostly been concerned with the inner workings of a landscape-system; — i.e. mainly slow process-response phenomena. However, the tectonic input (Principle of Tectonic Predesign) strongly influences the genesis of many geomorphic landscape features such as drainage systems, the shape of valleys, incised meanders, glacial forms, mass movements and other features: some common contentions (e.g. that water causes V-shaped, ice U-shaped valleys) are shown to be in need of modification.