  We review the phenomenology of ultra-high energy (UHE) neutrino detection.
The motivations for looking for such neutrinos stemming from observational
evidence and the potential for new physics discoveries are enumerated, and
their expected sources and fluxes are given. Cross-sections with nucleons all
the way upto neutrino energies of 10^20 eV, and the attenuation of the fluxes
in the earth are discussed. Finally, sample event-rates for existing and future
Water/Ice Cerenkov detectors are provided.
