  For contracting/expanding bouncing cosmologies, the formulation of junction
conditions at a bouncing was recently revisited by the author in collaboration
with B. Le Floch and G. Veneziano. The regime of interest here is the so-called
quiescent regime, in which a monotone behavior of the metric is observed and
asymptotic expansions can be derived. Here, we overview our new methodology
based on the notion of {\sl singularity scattering maps} and {\sl cyclic
spacetimes}, and we present our main conclusions. In particular, we provide a
classification of all allowed bouncing junction conditions, including three
universal laws.
