  Chiral perturbation theory is a very general expansion method which can be
applied to any dynamical system which has continuous global symmetries and in
which the ground state breaks some of these spontaneously. In these lectures we
explain at a basic level and in detail how such symmetries are identified in
the case of the QCD Lagrangian and describe the steps which are involved in
practice in the construction of a low-energy effective theory for QCD.
