  Neutrino astronomy beyond the Sun was first imagined in the late 1950s; by
the 1970s, it was realized that kilometer-scale neutrino detectors were
required. The first such instrument, IceCube, is near completion and taking
data. The IceCube project transforms a cubic kilometer of deep and
ultra-transparent Antarctic ice into a particle detector. A total of 5,160
optical sensors are embedded into a gigaton of Antarctic ice to detect the
Cherenkov light emitted by secondary particles produced when neutrinos interact
with nuclei in the ice. Each optical sensor is a complete data acquisition
system, including a phototube, digitization electronics, control and trigger
systems and LEDs for calibration. The light patterns reveal the type (flavor)
of neutrino interaction and the energy and direction of the neutrino, making
neutrino astronomy possible. The scientific missions of IceCube include such
varied tasks as the search for sources of cosmic rays, the observation of
Galactic supernova explosions, the search for dark matter, and the study of the
neutrinos themselves. These reach energies well beyond those produced with
accelerator beams.
  The outline of this review is as follows:
  Neutrino Astronomy and Kilometer-Scale Detectors. High-Energy Neutrino
Telescopes: Methodologies of Neutrino Detection. IceCube Hardware. High-Energy
Neutrino Telescopes: Beyond Astronomy. Future Projects
