  Results are presented from analyses of jet data produced in pbarp collisions
at sqrt{s} = 630 and 1800 GeV collected with the DO detector during the 1994-95
Fermilab Tevatron Collider run. We discuss details of detector calibration, and
jet selection criteria in measurements of various jet production cross sections
at sqrt{s} = 630 and 1800 GeV. The inclusive jet cross sections, the dijet mass
spectrum, the dijet angular distributions, and the ratio of inclusive jet cross
sections at sqrt{s} = 630 and 1800 GeV are compared to next-to-leading-order
QCD predictions. The order alpha_s^3 calculations are in good agreement with
the data. We also use the data at sqrt{s} = 1800 GeV to rule out models of
quark compositeness with a contact interaction scale less than 2.2 TeV at the
95% confidence level.
