  Many hadronic states observed since 2003, especially for the positive-parity
charm-strange states $D_{s0}^\ast (2317)$ and $D_{s1}(2460)$, do not conform
with the conventional quark model expectations and raise various puzzles in
charm meson spectroscopy. We demonstrate that those puzzles find a natural
solution thanks to the recent development of chiral effective theory and
Lattice simulations. The existence of the $D_{s0}^\ast (2317)$ and
$D_{s1}(2460)$ are attributed to the nonperturbative dynamics of Goldstone
bosons scattering off $D$ and $D^\ast$ mesons. It indicates that the lowest
positive parity nonstrange scalar charm mesons, the $D_0^\ast(2400)$ in the
Review of Particel Physics, should be replaced by two states. The well
constructed amplitudes are fully in line with the high quality data on the
decays $B^-\to D^+\pi^-\pi^-$ and $D_s^0\to \bar{D}^0K^-\pi^+$. This implies
that the lowest positve-parity states are dynamically generated rather than
conventional quark-antiquark states. This pattern has also been established for
the scalar and axial-vector mesons made from light quarks ($u$, $d$ and $s$
quarks).
