Neutrino masses and bimaximal mixing

Solar and atmospheric neutrino anomalies are described by bimaximal mixing of three Majorana neutrinos. Neutrino oscillations in appearance v_e ⇌ v_μ,v_τ and in disappearance v_e long baseline and atmospheric experiments are sensitive to deviations from the ideal bi maxi mal 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.