  The oscillation spectrum of Nu Eri is the richest known for any variable of
the Beta Cephei type. We interpret the spectrum in terms of normal mode
excitation and construct seismic models of the star. The frequency data
combined with data on mean colours sets the upper limit on the extent of
overshooting from the convective core. We use data on rotational splitting of
two dipole (l=1) modes (g_1 and p_1) to infer properties of the internal
rotation rate. Adopting a plausible hypothesis of nearly uniform rotation in
the envelope and increasing rotation rate in the mu-gradient zone, we find that
the mean rotation rate in this zone is about three times faster than in the
envelope. In our standard model only the modes in the middle part of the
oscillation spectrum are unstable. To account for excitation of a possible
high-order g-mode at nu = 0.43 c/d as well as p-modes at nu > 6 c/d we have to
invoke an overabundance of Fe in the driving zone.
