The nucleon is made of an outer, bosonic cloud (quark-antiquark condensate) and an inner core. The condensate breaks the chiral symmetry and its excitation spectrum, as seen in meson-nucleon reactions and in deep inelastic electron nucleon reactions, is of phonon type, satisfying Landau’s criterion for superfluidity (A. Mann and R.M. Weiner, Nuovo Cimento 10A (1972) 625). At a critical temperature of the order of 170 MeV, the superfluid undergoes a phase transition to a new state of matter, quark matter, in which the chiral symmetry is restored (S. Eliezer and R. M. Weiner, Phys.Rev. 13 (1976) 87). This phase transition is the subject of intensive experimental and theoretical search through heavy ion reactions.