Design of a safe slope or checking the safety of an existing one is an important and complicated problem in rock engineering. The main source of complication is the existence of uncertainties, which can be analyzed and quantified in a rational way only through probabilistic methods. This book explains the principles of reliability-based analyses and design of rock slopes that can easily be used by the practicing engineers. The first-order second-moment (FORM) method and Monte Carlo Simulation (MCS) procedure are adopted as the reliability assessment models and they are implemented for the case of plane failure. For the systematic analysis of uncertainties associated with the rock slope stability parameters, a model developed within the framework of first-order second-moment approach is presented. The implmentation of the described principles and approaches also illustarated with real case study examples