  The concept of Spontaneous Symmetry Breaking (SSB) represents a real
breakthrough for present description of fundamental interactions by means of
gauge theories. Although the underlying ideas were ancient, their formalization
required a long time, due to epistemological obstacles and technical
difficulties. In this paper, the main steps of SSB evolution are briefly
outlined, from the introduction of the order parameter in the Thirties to the
birth of the many-body theory at the end of the Fifties. In this context, the
contribute of the capital L.Landau's works on phase transitions and quantum
fluids, as well as of the seminal ideas of F. London, is highlighted, and the
phenomenological approach in theoretical physics (whose features are
schematically underlined) is showed to be crucial in the rising field of
complex systems.
