  Primordial nucleosynthesis is inevitable during the early evolution of an
expanding universe filled with radiation and matter (baryons). However, the
precise abundance yields depend sensitively on the baryon density, the
radiation content and the early expansion rate. For ``standard" big bang
nucleosynthesis (SBBN) only D, $^3$He, $^4$He and $^7$Li are produced in
astrophysically interesting abundances which depend on only one ``free"
parameter, $\eta = n_{\rm B}/n_{\gamma}$, the ratio of baryons (nucleons) to
photons. With four primordial abundances and one adjustable parameter, SBBN is
an eminently testable theory. In the confrontation of theory with data current
observations suggest a crisis traceable to the tension between deuterium
(favoring a ``high" value of $\eta$) and helium-4 (preferring a ``low" $\eta$
value). In this contribution, the written version of the material I discussed
at the Princeton University ``Critical Dialogues in Cosmology" (June 1996), I
will present the case for a conflict and show how recent observations of
deuterium in nearly primordial QSO absorbers exacerbate the problem. I conclude
with a brief description of an alternate, ``dynamical" approach to bounding the
nucleon density which may be of some value given the current deuterium
dichotomy.
