  Recent atmospheric neutrino data at Super-Kamiokande suggest the near-maximal
flavor mixing. Models for the lepton mass matrix, which give the near-maximal
flavor mixing, are discussed in this report. Mass matrix models are classified
according to the mechanism providing the large flavor mixing, and those are
reviewed briefly. "Naturalness" of the mass matrix is also discussed in order
to select the neutrino mass matrix. Details of the mass matrix with the $S_3$
flavor symmetry are presented.
