  In the first thousand seconds of its evolution the Universe was a primordial
nuclear reactor synthesizing the nuclides D, $^3$He, $^4$He and $^7$Li. These
messengers from the Big Bang provide a unique window on the early, hot, dense
Universe, offering the opportunity for tests of the standard models of particle
physics and of cosmology. A new, statistically coherent comparison of the
primordial abundances of these nuclides inferred from increasingly accurate
observational data with those predicted by the standard model hints at a
possible crisis. The case for this emerging crisis is presented and several
paths towards ameliorating it are explored.
