  We present recent results on light mesons based on Dalitz plot analyses of
charm decays from Fermilab experiment E791. Scalar mesons are found to have
large contributions to the decays studied, $D^+\to K^-\pi^+\pi^+$ and $D^+,
D_s^+\to\pi^-\pi^+\pi^+$. From the $K\pi\pi$ final state, we find good evidence
for the existence of the light and broad $\kappa$ meson and we measure its mass
and width. We also discuss recently published results on the 3$\pi$ final
states, especially the measurement of the $f_0$ parameters and the evidence for
the $\sigma$ meson from $D^+\to\sigma\pi^+$. These results demonstrate the
importance of charm decays as a new environment for the study of light meson
physics.
