  We summarize the progress made during the last few years on the study of
Vassiliev invariants from the point of view of perturbative Chern-Simons gauge
theory. We argue that this approach is the most promising one to obtain a
combinatorial universal formula for Vassiliev invariants. The combinatorial
expressions for the two primitive Vassiliev invariants of order four, recently
obtained in this context, are reviewed and rewritten in terms of Gauss
diagrams.
