[en] Data for J/psi production with nucleon and pion beams are used, together with electroproduction data, to extract information about distributions of quarks within hadrons. These distributions are used to make predictions about J/psi production with beams of hadrons of various types, and about the production of lepton pairs. It is argued that, even at SPS or FNAL energies, J/psi production does not usually involve the conjoint production of charmed particles. The production of charmed particles without the J/psi is also considered. The cross section is estimated to be smaller than has been previously predicted. (Auth.)