Planar silicon strip sensors became very popular in the last two decades in inner tracking systems of large-scale particle physics experiments, like the CMS detector at CERN's new particle accelerator LHC (Large Hadron Collider). With its more than 24,000 sensors it currently represents the largest silicon tracker in the world. This book reviews the quality assurance scheme established for testing those silicon sensors. It describes the full readout chain and delivers results from first tests of the tracker as a whole. The book concludes with a discussion about conceptual problems in the current design and proposes potential improvements for future projects like the proposed International Linear Collider.