The differential cross section for deuteron production in proton-proton collisions was measured for incident proton kinetic energies of 1.55, 2.5, and 2.9 GeV. Measurements were made at laboratory angles of 5.9, 11.55, 15.72 degrees, and at the two higher energies, at 20 degrees relative to the beam direction for deuteron laboratory momenta in the range 1.0-2.4 GeV/c. The center of mass differential cross section distributions obtained at the three energies of this experiment showed a general similarity to one another. The total deuteron production cross section decreased monotonically with incident proton kinetic energy. The cross section for production of deuterons associated with two or more pions had a maximum near 2 GeV. A search for pion resonances of unit isotopic spin in the mass range 400-1000 MeV through reactions of the form p + p to d + positive-x yielded evidence for RHO meson production. The laboratory distributions in momentum and angle of deuterons produced in proton-proton collisions at 2.9 GeV were found to be much different from those arising from proton-beryllium and proton-platinum collisions at the same energy.