  Following a brief introduction to early Universe cosmology, the current of
status of big bang nucleosynthesis is reviewed and the concordance between
theory and observation is examined in detail. The abundances of He4 and Li7
determine the value of the baryon-to-photon ratio, $\eta$ to be relatively low,
$\eta \approx 1.8 \times 10^{-10}$, and agrees with some recent measurements of
D/H in quasar absorption systems. These results have far reaching consequences
for galactic chemical evolution, the amount of baryonic dark matter in the
Universe and on the allowed number of degrees of freedom in the early Universe.
Finally, motivations for cosmological dark matter will be reviewed with special
emphasis placed on supersymmetric candidates.
