Predicting quark and lepton masses and mixings

A model is presented that fits the quark and lepton masses and mixings wher ein five dimensionless parameters and a phase account for fifteen dimension less observables. Among these are the Wolfenstein parameters rho and eta, t he nu(e) - nu(mu) and nu(e) - nu(tau) mixing angles which are predicted to be small and comparable while the nu(mu) - nu(tau) mixing angle is predicte d to be large. The model is based on supersymmetric SO(10) with the form of the mass matrices motivated by simplicity at the level of grand unificatio n. (C) 1999 Published by Elsevier Science B.V. All rights reserved.