Impression in Removable partial denture is negative replica of oral and its sourrounding structures.The success of a removable partial denture, the comfort for the patient, stability and especially the psychological acceptance depend on a series of essential technicals factors. Probably the more delicate stage of the prosthetic technology is the transfer of informations from the mouth of the patient to the prothesist through the impression. In removable partial denture, impression have to take account into the balance between uncompressible hard tissue and soft structures with variable compressibilities. The diversity of clinical cases is responsible for a large diversity of techniques. The aim of this book is to describe the more common techniques used in every day practice.