Guaranteed-Service Model (GSM) approach for the safety stock placement problem aims at finding the optimal placement of safety stocks in a multi-echelon inventory system under bounded demand and guaranteed service times. Although this model has been present for more than fifty years, the last decade witnessed a growing interest. Recent works include new versions of the problem with relaxed assumptions and efficient solution methods for different supply chain network topologies. The purpose of this paper is to review and summarize the literature on the GSM and to suggest future research directions.