  We review the status of integrable models from the point of view of their
dynamics and integrability conditions. Some integrable models are discussed in
detail. We comment on the use it is made of them in string theory. We also
discuss the Bethe Ansatz solution of the SO(6) symmetric Hamiltonian with SO(6)
boundary.
  This work is especially prepared for the seventieth anniversaries of
Andr\'{e} Swieca (in memoriam) and Roland K\"{o}berle.
