  We suggest mass matrices for neutrinos and charged leptons that can explain
solar and atmospheric neutrino data. The resulting flavor mixing matrix
$V_{\nu}$ has a property that $(V_{\nu})_{13}=0$, thus making $\nu_e
\leftrightarrow \nu_{\mu}$ and $\nu_{\mu} \leftrightarrow \nu_{\tau}$
oscillations to be effectively a two-channel problem. Phenomenological
consequences of the lepton mass matrix ansatze are consistent with the current
data on various type of neutrino oscillation experiments except the LSND
measurement. %and that three neutrinos are almost degenerate in mass. Three
neutrinos, being almost degenerate with $\sum | m_{\nu_i} | \lesssim 1 $ eV,
can be a part of hot dark matter without any conflict with the constraint from
neutrinoless double beta decay experiments. The $\nu_{\mu} \leftrightarrow
\nu_{\tau}$ oscillation, $\sin^2{2\theta_{\mu \tau}}$, is predicted to be
0.86-0.97 with $\Delta m^2_{\mu \tau}\simeq 2 \times 10^{-3} {eV}^2$, which is
consistent with the atmospheric neutrino data and can be tested further at the
planned MINOS and K2K experiments searching for $\nu_{\mu} \to \nu_{\tau}$
oscillation.
