  This paper describes salient features of new sets of parton distributions
obtained by the CTEQ Collaboration based on a comprehensive QCD global analysis
of all available data. The accuracy of the new data on deep inelastic
scattering structure functions obtained by the very high statistics NMC and
CCFR experiments provides unprecedented sensitivity to the flavor dependence of
the sea-quark distributions. In addition to much better determination of the
small x dependence of all parton distributions, we found: (i) the strange quark
distribution is much softer than the non-strange sea quarks and rises above the
latter at small-x; and (ii) the difference $\bar d-\bar u$ changes sign as a
function of x. A few alternative sets of viable distributions with conventional
assumptions are also discussed.
