  I argue that the observed flavor structures of leptons and quarks might imply
the existence of certain flavor symmetries. The latter should be a good
starting point to build realistic models towards deeper understanding of the
fermion mass spectra and flavor mixing patterns. The \mu-\tau permutation
symmetry serves for such an example to interpret the almost maximal atmospheric
neutrino mixing angle (\theta_23 \sim 45^\circ) and the strongly suppressed
CHOOZ neutrino mixing angle (\theta_13 < 10^\circ). In this talk I like to
highlight a new kind of flavor symmetry, the Friedberg-Lee symmetry, for the
effective Majorana neutrino mass operator. Luo and I have shown that this
symmetry can be broken in an oblique way, such that the lightest neutrino
remains massless but an experimentally-favored neutrino mixing pattern is
achievable. We get a novel prediction for \theta_13 in the CP-conserving case:
\sin\theta_13 = \tan\theta_12 |(1- \tan\theta_23)/ (1+ \tan\theta_{23})|. Our
scenario can simply be generalized to accommodate CP violation and be combined
with the seesaw mechanism. Finally I stress the importance of probing possible
effects of \mu-\tau symmetry breaking either in terrestrial neutrino
oscillation experiments or with ultrahigh-energy cosmic neutrino telescopes.
