The cross sections and forward-backward asymmetries of hadronic and leptonic events produced in e+e− collisions at centre-of-mass energies from 130 to 183 GeV are presented. Results for e+e− , μ+μ− , τ+τ− , qq¯ , bb¯ and cc¯ production show no significant deviation from the Standard Model predictions. This enables constraints to be set upon physics beyond the Standard Model such as four-fermion contact interactions, leptoquarks, Z′ bosons and R-parity violating squarks and sneutrinos. Limits on the energy scale Λ of e+e−ff¯ contact interactions are typically in the range from 2 to 10 TeV. Limits on R-parity violating sneutrinos reach masses of a few hundred GeV/ c2 for large values of their Yukawa couplings.