Status and commissioning of the CMS experiment

The status of the construction and installation of CMS detector is reviewed. The 4T magnet was commissioned during the Summer 2006. A Cosmic Challenge in which elements of the final detector were involved, allowed a review of the full system. The detector first assembled on the surface is progressively installed in the experimental cavern. A second part of the document is devoted to a discussion of the general commissioning strategy of the CMS experiment, with a particular emphasis on trigger, calibration and alignment. Examples for early physics with CMS are also presented.