  Recent developments in theory and phenomenology relevant to deep inelastic
lepton scattering are reviewed, concentrating on the following topics:
Predicted behaviour of non-singlet and polarized structure functions at small
$x$; Theoretical studies of saturation and unitarity effects at small $x$ in
quarkonium scattering; Renormalons and higher twist contributions;
Next-to-leading-order calculations of jet cross sections; Forward jet
production as a probe of small-$x$ dynamics.
