The third edition of Theoretical Geomorphology is completely rewritten and up-dated including fractal geometry, general systems theory and problems of "roads to chaos". It also includes the mechanics of slope formation, the theory of river action, the system theory of landscape evolution, the theory of aquatic effects, the theory of glacial and periglacial forms and the theory of aeolian and desert features. The reader will find a complete review of the theory of the genesis of the Earth's surface features.