  We propose a simple texture of the neutrino mass matrix with one sterile
neutrino along with the three standard ones. It gives maximal mixing angles for
$\nu_e \to \nu_S$ and $\nu_\mu \to \nu_\tau$ oscillations or vice versa. Thus
with only four parameters, this mass matrix can explain the solar neutrino
anomaly, atmospheric neutrino anomaly, LSND result and the hot dark matter of
the universe, while satisfying all other Laboratory constraints. Depending on
the choice of parameters, one can get the vacuum oscillation or the large angle
MSW solution of the solar neutrino anomaly.
