  We consider the nonrelativistic interacting Bose gas at zero and finite
temperature. Using the 1/N-expansion, we derive expressions for the free energy
density and the number density to next-to-leading order in 1/N. Outside the
critical region and at weak coupling, our calculations reduce to the well-known
mean-field results for the dilute Bose gas. We also rederive the
nonperturbative critical density for Bose condensation which was first
calculated by Baym, Blaizot, Holzmann, Lal\"oe, and Vautherin.
