This book is composed of two phases. The first phase deals with the generalities of landslides, their classifications and the different methods of landslide analysis. The second phase deals with a comparative study of landslides (Case of Parc Dounia Alger, ALGERIA), this comparison was made by two software (PLAXIS and GEOSLOP) with a different calculation basis. The first one is based on the finite element method with the technique of mechanical parameters reduction (c-phi reduction) until failure. The second is based on limit equilibrium methods.