This chapter discusses the basic formulation of 2D slope stability methods will be discussed. Brief discussion of 3D analysis and the uses of some more advanced methods. Landslides have been a problem in many developed cities all over the world. In Hong Kong, landslides have caused loss of life and property damage. The factor of safety F for slope stability analysis is commonly defined as the ratio of the ultimate shear strength divided by the mobilised shear stress at the verge of failure, though other definitions also exist. Under all the common classical approaches, slope stability analysis is a statically indeterminate problem. Different assumptions have to be adopted so that the problem can be solved. The sliding body over the failure surface is divided into a finite number of slices which are usually cut vertically, but horizontally as well as inclined cut slices have also been used by various researchers.