  Solar and atmospheric neutrino anomalies are described by bimaximal mixing of
three neutrinos. Neutrino oscillations in appearance nu_e <--> nu_mu,nu_tau and
in disappearance nu_e long baseline and atmospheric experiments are sensitive
to deviations from the ideal bimaximal mixing. It is suggested that these
deviations may be dominated by a rotation in the electron--muon plane of the
generation space. Simple seesaw models are described supporting this idea. The
rotation angle is estimated from Fritzsch's relation. Predictions are presented
for oscillations in long baseline experiments, for solar neutrinos, and for the
rates of neutrinoless double beta decays.
