  The reaction $\pi^{-}p \to \eta n$ is investigated within a dynamical
coupled-channels model of meson production reactions in the nucleon resonance
region. The meson baryon channels included are $\pi N$, $\eta N$, $\pi \Delta$,
$\sigma N$, and $\rho N$. The non-resonant meson-baryon interactions of the
model are derived from a set of Lagrangians by using a unitary transformation
method. One or two excited nucleon states in each of $S$, $P$, $D$, and $F$
partial waves are included to generate the resonant amplitudes. Data of
$\pi^{-}p \to \eta n$ reaction from threshold up to a total center-of-mass
energy of about 2 GeV are satisfactorily reproduced and the roles played by the
following nine nucleon resonances are investigated: $S_{11}(1535)$,
$S_{11}(1650)$, $P_{11}(1440)$, $P_{11}(1710)$, $P_{13}(1720)$, $D_{13}(1520)$,
$D_{13}(1700)$, $D_{15}(1675)$, and $F_{15}(1680)$. The reaction mechanism as
well as the predicted $\eta N$ scattering length are discussed.
