  ${\rm B - L}$ cosmic strings form in a wide class of theories beyond the
Standard Model which contain a ${\rm U}(1)_{{\rm B - L}}$ gauge symmetry. They
can form at the end of hybrid inflation and explain, together with inflation,
the Cosmic Microwave Background anisotropies and the formation of large scale
structure. They can produce Cold Dark Matter in the form of the Lightest
SuperParticle and they can be at the origin of the baryon asymmetry of our
universe. One major advantage of these mechanisms is that they are non-thermal.
