  We present a theoretical review of the possibilities offered by heavy flavour
tagging in testing QCD features in 4-jet events at LEP1. Attention is focused
mainly on the properties of the angular variables which are used in the
experimental analyses to measure the colour factors of the strong interactions.
We also comment on a possible settlement of the ongoing controversy about the
existence in LEP1 data of SUSY events involving light gluinos. Integrated and
differential rates of interest to phenomenological analyses are given and
various tagging procedures are discussed.
