  A high precision study of the process gamma gamma -> p p-bar has been
performed using a data sample of 89/fb collected with the Belle detector at the
KEKB e+e- collider. The cross section of p p-bar production has been measured
at two-photon center-of-mass (c.m.) energies between 2.025 and 4.0 GeV and in
the c.m. angular range of |cos(theta^*)|<0.6. Production of gamma gamma ->
eta_c -> p p-bar is observed and the product of the two-photon width of the
eta_c and its branching ratio to p p-bar is determined.
