Few-body problems in hadron spectroscopy

Some rigorous results call be derived using a very simple approach to hadro n spectroscopy, in which a static potential is associated with non-relativi stic kinematics. Several regularities of the experimental spectrum are expl ained by such models. It is underlined that certain methods developed for h adronic physics have found applications in other fields, in particular atom ic physics. A few results carl be extended to cases involving spin-dependen t forces or relativistic kinematics.