The Kilometer-scale IceCube neutrino detector is a discovery instrument that addresses issues of nuclear & particle physics, cosmology and astronomy. Examples of the many multidisciplinary missions include searches for dark matter particles and for small extra dimensions of space-time. Its design is very much driven by the observational fact that Nature accelerates cosmic-ray electrons and protons to energies that exceed one hundred and one hundred million TeV, respectively. This energy range sets the required size scale of cosmic-ray neutrino telescopes. For the past five decades, the problem has been how to develop a robust technology to the build an affordable kilometer-scale neutrino detector that can access the science. The IceCube detector uses ultra-clear deep Antarctic ice as a Cherenkov-light detector of muons and showers of particles that produced by ultra-high energy neutrinos from distant regions of the universe. The instrument, which is essentially completed, collects over 100 events per day caused by neutrinos that are produced by cosmic-ray interactions in the upper atmosphere. Although these are not of great cosmological interest, they provide important calibration reactions that have demonstrated that the instrument has a sensitivity that exceeds expectations. The first scientific results from IceCube already show indications of exciting science.