  The Antarctic Muon and Neutrino Detector Array (AMANDA) began collecting data
with ten strings in 1997. Results from the first year of operation are
presented. Neutrinos coming through the Earth from the Northern Hemisphere are
identified by secondary muons moving upward through the array. Cosmic rays in
the atmosphere generate a background of downward moving muons, which are about
10^6 times more abundant than the upward moving muons. Over 130 days of
exposure, we observed a total of about 300 neutrino events. In the same period,
a background of 1.05*10^9 cosmic ray muon events was recorded. The observed
neutrino flux is consistent with atmospheric neutrino predictions. Monte Carlo
simulations indicate that 90% of these events lie in the energy range 66 GeV to
3.4 TeV. The observation of atmospheric neutrinos consistent with expectations
establishes AMANDA-B10 as a working neutrino telescope.
