Summary of Recent Developments in Primordial Nucleosynthesis *

This paper summarizes the recent observational and theoretical results on Big Bang Nucleosynthesis. In particular, it is shown that the new Pop II 6 Li results strongly support the argument that the Spite Plateau lithium is a good estimate of the primordial value. The 6 Li is consistent with the Be and Be found in Pop II stars, assuming those elements are cosmic ray produced. The HST 2 D value tightens the 2 D arguments and the observation of the 3 He in planetary nebula strengthens the 3 He + 2 D argument as a lower bound on Ω b . The new low metalicity 4 He determinations slightly raise the best primordial 4 He number and thus make a better fit and avoid a potential problem. The quark‐hadron inspired inhomogeneous calculations now unanimously agree that only relatively small variations in Ω b are possible vis‐à‐vis the homogeneous model; hence, the robustness of Ω b ∼ 0.05 is now apparent. A comparison with the ROSAT cluster data is also shown to be consistent with the standard BBN model. Ω b ∼ 1 seems to be definitely excluded, so, if Ω= 1, as some recent observations may hint, then non‐baryonic dark matter is required.