  We consider the parameters of an entry-level neutrino factory designed to
make the first observation of nu_e -> nu_mu oscillations, measure the
corresponding amplitude sin^2 2theta_{13}, and determine the sign of the
atmospheric-scale delta m_{32}^2 via matter effects. A 50 kt detector, a stored
muon energy E_mu geq 20 GeV and 10^{19} muon decays would enable these goals to
be met provided sin^2 2theta_{13} > 0.01. The determination of the sign of
delta m_{32}^2 also requires a baseline L geq 2000 km. An upgraded neutrino
factory with O(10^{20}) decays would enable the first observation of nu_e ->
nu_tau oscillations. With O(10^{21}) decays the effects of a large CP-phase
could be measured in the case of the large angle matter oscillation solution to
the solar neutrino anomaly. Our analysis includes a family of three-neutrino
models that can account for the atmospheric and solar neutrino oscillation
indications.
