IceCube Neutrinos: From GeV to PeV

Detecting neutrinos associated with the still enigmatic sources of cosmic rays has reached a new watershed with the completion of IceCube, the first detector with sensitivity to the anticipated fluxes. In this review, we will revisit the rationale for constructing kilometer-scale neutrino detectors. We will subsequently discuss progress towards achieving the main scientific goals of IceCube in the context of data taken mostly during construction.