  Some basic concepts are discussed to derive renormalisation factors of local
lattice operators relevant to deep inelastic structure functions and to other
measurable quantities. These $Z$ factors can be used to relate matrix elements
measured by lattice techniques to their continuum counterparts. We discuss the
$O(a)$ improvement of point and one-link lattice quark operators. Suitable
bases of improved operators are derived. Tadpole improvement is applied to get
more reliable perturbative results.
