The Silicon Strip Tracker (SST) is the intermediate part of the CMS Central Tracker System. SST is based on microstrip silicon devices and in combination with pixel detectors and the Microstrip Gas Chambers aims at performing pattern recognition, track reconstruction and momentum measurements for all tracks with p(T) greater than or equal to 2 GeV/c originating from high luminosity interactions at root s = 14 TeV at LHC. We aim at exploiting the advantages and the physics potential of the precise tracking performance provided by the microstrip silicon detectors' on a large scale apparatus and in a much more difficult environment than ever. In this paper we describe the actual SST layout and the readout system.