First Physics at CMS

The year 2008 marked the completion of the Large Hadron Collider (LHC) and the LHC detectors. The construction and commissioning of these scientific instruments, unprecedented in scale, complexity and precision, involved a number of challenging physics measurements and analyses, even before the first proton-proton collisions. This report highlights a selection of such physics measurements for and by the Cosmic Muon Solenoid (CMS) detector. These first physics analyses at CMS illustrate the depth of our understanding of the detector and demonstrate its readiness for data taking.